I saw an interesting thread on MMO-Champion about an imperial player asking about the storylines for the Republic classes, so I thought I would hijack the idea to get people's impressions. Ignoring gameplay, what do you think about the Class Storylines thus far?
Trooper: For the Beta-Weekend I played Trooper and I did like their story. Its basically Mass Effect in the Star Wars universe. That's not a bad thing though, because it is well done. You would probably enjoy this storyline if you are less interested in the mystical and more interested in military/spec ops type of flavors. One thing I REALLY enjoy about the Trooper storyline was that Dark Side choices didn't make you feel "evil". Basically it was very much akin to the "Renegade" responses. I found my Trooper responding fairly evenly between Light and Dark based on the situation (I won't kick a man when he's down, but if saving a handful of people slows me down from diffusing a bomb that could kill hundreds then those needy people are on their own).
Jedi Knight: Right now on live I've played a Jedi Knight up to level 44 and am pretty far in the JK Storyline. Honestly its pretty good. The tasks are repetative in that it seems to be all about stopping the bazillion doomsday devices all over the place. Its actually a little exhausting and disconcerting that their are so many ways the Empire has to be gifted with an "I Win" button in the JK story. That being said, you really do get to play like a Knight crusading through the galaxy. Light Side/Dark Side choices seem to revolve around whether you are focused on completing the objective at all costs (I.E. sacrificing others) or whether you are willing to make things harder on yourself to do the right thing. But as many people have mentioned, JK has one of the most bad ass (from a Republic standpoint) confrontations of all classes. If you were making a movie based on SWTOR then the main character would be the JK.