Unfortunately, I must say that right now this game is a flop.
It its unbearable and I don't care what anyone says. This general discussion forum is FULL of posts about how LOTS of people are not enjoying this game and the reasons are very consistent.
My recommendation is to not buy this. I don't take my purchase as a loss because I think a lot of this will be fixed in time. That being said, don't expect to buy this game and enjoy it. I made that mistake.
This site is also FULL of posts from LOTS of people (who often time have better gaming credentials than the 2 post whiners) who love the game and understand what is actually going on. 8/10(Yeah I been keeping a tally) bad game posts are by people who unwittingly post complaints of issues that only show their lack of experience with mmo launches and/or incompetence with a computer. The consistent posts are sadly often people who either cannot grasp simple concepts or who want this game to just uproot and become WoW or some other game right this instant. Then there's the rest who want rational fixes and additions for things that the game potentially could be better with. I get those people and can't complain a ton about that.
There are problems with this game but I would say there are less problems than the norm in the first week of launch. The gameplay is fun the story is good(well, what of it is found/released) and the servers and UI need a bit of love. There are also a few staples of an mmo that aren't in game. Having played open beta tho and got my hands on some retail SE has improved this game in leaps and bounds in the last month. I'm sure more is coming.
OP: This site has a bunch of information in the database on all the classes and abilities. If you want to see the classes in action go to youtube and look for "Rocslock" He has posted a lot of gameplay videos thorughout beta and as far as I'm aware is still posting them. That will give you an idea of what the classes look like playing. As for races it seems not to make a lot of difference. They left a lot more up to how you spec than what race you choose this time. Some races may be a minimal amount of points better than the next at a task but in the end I don't think many will ever notice a Race particularly sucking at a class.