I'm a fanfic writer and a long-time reader from Australia, though I can't say how long- primarily because I don't know how long it's been myself. My primary focus of interest is Ranma 1/2, but I browse through many, many other areas. I'll read just about anything, but I can't stand slash or poor writing/plots/grammar/characterization in general, or Ranma/Akane and "Ranma embraces his feminity" type fics in particular. The last one especially gets my goat because it's so completely out of character: Ranma outright loathes his curse in the beginning and grudgingly learns to tolerate it, partly because he finds it useful for getting free food and primarily because he just can't find a way to get rid of it. Were he a bit more ruthless or adept at forethought, he'd have undoubtedly either realised he could simply charm either of the Kunos into paying for a return plane ticket to China or simply walked away from the Tendos and swam there- he did it to reach Jusenkyo in the first place, he can do it again.
I always work with the anime canon for Ranma 1/2, primarily because it's the canon I'm most familiar with and partially because it's the canon I prefer. Let's get one thing straight- the anime didn't ignore the latter stories of the manga (Herb and the Musk, Umisenken/Yamasenken fight, battle with Saffron) on purpose, it went out of business four years before the author finished the manga. In a way, that's a good thing, because the longer-going manga suffers character decay- compare Nabiki's dealings with Kuno when she first sold him the photos of "the pigtailed girl" to the wedding, where she sold off details about it simply for the money gifts that would be delivered. A similar situation comes to mind with the Inuyasha anime vs. its manga version; the anime finished at around 167 episodes- but if you expand that continuity to include the movies, the group have finally defeated Naraku already, whereas in the manga it's over 500 volumes and the climatic showdown still hasn't happened. Every time they finally get face to face with the real Naraku, he whips out a new defence that makes him impervious to their attacks and they need to find another new thing to break through it- is he supposed to be a yokai or a cockroach-god?
I mentioned above that I hate Akane/Ranma fanfics- in part, this is because they're so mainstream. Not only are they the "one true couple" (how that phrase makes me want to puke) of the canon, but the fanfics about them are so damn common and cliche. I haven't read a focused Akane/Ranma yet that I could stand to finish. Another reason is that I loathe Akane- while I admit she has her good moments, her bad ones and ugly deeds far outweigh them. This applies to both canons- anime-Akane might be more consistently bad, but in my opinion that makes her better than the manga version, where her outbursts are more extreme because they can be constrasted to her more usual behavior. Manga-Akane also goes to "ugly-class" moments far more often than anime-Akane does. One of her manga-moments I hate the most is the infamous "if you hit me, I'll never forgive you!" line she comes up with in the Battle-Dogi storyline. Ranma had good reason to be upset in that storyline; as we've seen before, Ranma's martial arts prowess matters greatly to him- in Super Soba, he cries after Akane defeats him at arm-wrestling, proving she's stronger than he is, and in the Ultimate Weakness Moxibustion storyline, he admits that his strength is all he has. That doesn't mean that the behavior he went to earlier wasn't a nasty moment for him as well. However, it's not simply how that line applies to that situation that bugs me, but what it implies retroactively: throughout the manga, we have seen Akane clobber Ranma mercilessly whenever he does something she doesn't like, yet Ranma has always forgiven her and forgotten about it. And now, she's saying that if he dares to touch her in anger, she won't forgive him? What gives her the bloody right to say that!? An anime moment that's equally ugly is pretty much the entirety of "Ranma, You're Such a Jerk!"- in this episode, Akane runs away from home (secretly, she climbs onto the roof) and sends the whole family searching town all night in worry, simply because Ranma accidentally destroyed a pie she made- a deed for which he genuinely apologised.
So, these are my opinions of the girls, as based on the anime, with perhaps some notes on how they stack up against their manga counterparts.
Akane:
It's only by keeping her moments of kindness and friendliness in mind that I can resist the urge to simply wave her away as a noxious little pest that Ranma should dump. Even with those, however, Akane Tendo is and shall always be, in my opinion, a spoiled brat. She has her own personal view of herself as superior, and refuses to allow anything to contradict it- Akane would much rather believe Ryoga's lies about her food tasting great than Ranma's honest truth that it's unfit for human consumption. Whenever Ranma, too blunt and unschooled in social niceties to know better, points out her all-too-real flaws, she attacks him. Notice that when she cooks, Soun and Genma refuse to eat her food, but she doesn't strike them, now does she? There are many moments of nasty behavior, but one key example that I think exemplifies it comes from early in the story, the introduction of P-chan. When she sees Ranma-girl chasing the strange pig out of the bathroom, claiming that it attacked her, and when it attacks her again, her reaction to Ranma defending herself is to grab Ranma's breast and simulataneously squeeze it and pull it- HARD. It doesn't take a genius to know that this HURTS.
Kodachi:
In contrast to her manga version, the anime Kodachi is merely eccentric, though her actions in "A Leotard is a Girl's Burden" seem more in fitting with her counterpart than with the Kodachi we see throughout the rest of the anime. Compared to Kuno, she's actually quite sane- merely out of touch with the way things are supposed to work in society, which fits given that it's likely she was reared primarily by Sasuke. Unlike Kuno, she hasn't seen Ranma change shapes and thus has a valid reason for believing them to be different individuals. She has displayed quick wits, tactical thinking (along with few morals, but Ranma is no great moral pillar himself) and is basically far from stupid, while her brother and her father give off the impression of barely having three braincells between them. In short, I could see a matchup between Ranma and the anime version of Kodachi actually working, while the manga version is far too dangerous and unstable for Ranma to ever be attracted to her.
Ukyo:
The "cute fiancee", and a well-earned name it is. Ukyo's behavior and general demeanor are far more pleasant to me than Akane's. She's no saint, but frankly, sainthood is overrated- and in this sort of race, niceties will make you lose. She was willing to set Ryoga and Akane up on a date? Good tactical thinking, that's my opinion. Throwing those spatulas in the classroom? Marksmanship is vital to any martial artist who uses projectiles -even Mousse always hits what he's aiming at (even if it's not what he intended to be aiming at)- there was no danger to anyone but Ranma. There's also an element of underdog here; she has absolutely nobody to back up her claim but she herself. Akane has her family and Ranma's, Shampoo has Cologne, even Kodachi can bribe Genma to support her, but Ukyo has nobody. So, Ukyo is my second favorite matchup for Ranma, and maybe one day I'll actually post something about the two of them.
Shampoo:
Now we come to the number one girl for Ranma, in my opinion. Shampoo is, canonically, the most powerful of all the female martial artists that make up Ranma's romantic options, and has lived the life closest to the one Ranma has lived- that means she has the easiest time understanding him. She has her flaws, but she admits she has them, and frankly I prefer someone who openly admits that they'll do anything to win over a hypocrite who constantly babbles on about honor and duty whilst completely ignoring them (Soun, Happosai, Genma too when he gets in the mood). Shampoo genuinely loves Ranma; she was heartbroken when she left believing Ranma to be a real girl, and ecstatic when she found he was truly a boy. She willingly sided against her great-grandmother, undoubtedly an authority figure as a Joketsuzoku as well as her family matriarch, during the final battle for the Phoenix Pill, and she sabotaged Mousse's efforts during his first official match after his return from China- if all she wanted was the strongest man, she'd have let the two duke it out honestly. Cologne herself admits that Shampoo is in love with him and that her feelings run stronger than even Cologne had thought during "Two Too Violent Girls! Ling-Ling and Lung-Lung!", where Shampoo is willing to give the Kiss of Death to the young twins who have evidently looked up to her their whole lives in order to save Ranma. True, she uses love magic a bit too freely for my comforts, but given how common magic is amongst the Joketsuzoku (in the manga, they have a whole chest full of magical toys at the Cat Cafe), it may not have any social stigmata.