Personally, I think that when we're discussing this whole issue of Edward v. Jacob, as you pointed out, it will depend entirely on what you are trying to argue. Like you mentioned, it can be interpreted as:
A) Who is better for Bella?
B) Who is more justified in their actions throughout the series?
and C) Who do you prefer regardless of what's written in the books?
In short, these are my answers:
B) Jacob and Edward
... and these are my reasonings!
A) It is undoubtedly clear that Edward is the right one for Bella. I don't even think there's a point arguing Jacob's case. From the get-go, in an almost Romeo-&-Juliet-esque fashion, Edward and Bella fall for each other. Hard. If Jacob had the slightest chance, it would have been mentioned on the first meeting between them, when Bella arrived in Forks. Moreover, New Moon is absolutely littered with Jacob being close but never enough for Bella. Jacob would suffice but he never would be able to fill Edward's shoes... which is weird, 'cause you'd think Jacob would have bigger feet. lol, I digress. In short, as much as I like Jacob the character, there is no denying that gooshy, lovey-dovey connection between Edward and Bella.
I mean, when I was reading those parts where they were talking about how much they love each other, that connection, and even more so, how much his 'liquid gold' eyes or his Adonis-like, granite chest made her weak in the knees.... I think I had to put down the book to check how my masculinity is doing.
B) You can make a topic about this. This is like an essay topic.
C) Hands down, Jacob. I think people fail to see how realistic Jacob is as a character, aside from his ... well, shapeshifting, space heater abilities. Like a good friend of mine pointed out, it is probably his realism and therefore, more pronounced flaws, that make other readers turn the other cheek. Yes, he is not mature and yes, he is not very sensitive... but he is fresh out of puberty with hormones being pumped at dangerous levels. Not to mention the fact that he's dealing with an unrequited love and sexy, sweet-smelling vampires. That's enough to give most people cardiac arrest - good thing he's a werewolf. lol
Jokes aside though, I like Jacob because I could relate easier with him. I understand how Edward makes the girls swoon, and you know, he's not too shabby of a guy too. I mean, I read this series to see how this vampiric fictional character is doing this. I just think that he's a bit too perfect, and therefore a bit too unrealistic... and therefore, very hard to relate to. Jacob just has that human factor in him that, aside from the most obvious reasons, Edward lacks.
PS. It may be also because if I tried watching someone sleep and using "you fascinate me" as a reason, I will most likely get a shot in the babymaker and a restraining order instead of a glomp followed by a snog.
Wow, I'm glad I got some of that out of my chest. WHAT ARE YOUR OPINIONS?