I've put in enough time to get to level 15. I've only had 4 days to work with, but impressions so far -
1. The combat is very very slow, whether you like that sort of thing or not. In comparison to wow where you can 2-3 shot someone, it can take 10-30 hits to kill someone 1 on 1. Personally I find it unsatisfying to hit someone 18 times and then have them run away.
It feels like I'm nibbling on their ear instead of swinging a giant axe.
2. Heals are overpowered to hell, a good healer makes or breaks a match in rvr easily. You can take 12 swings at a guy in 15 seconds of time (usually while you're getting battered by 1-3 other guys), and 1 heal can reverse what ever damage you've done.
3. The melee dps has no place in the game as of right now. If you rush into a battle as a tank, you'll feel good knowing that you're soaking up hits for your casters. If you rush into battle as a caster, you'll feel good throwing those 400 damage fireballs (talking about tier 2) or healing the shit out of your teammates. If you rush into battle as melee dps, you know you can kind of take a few hits and that you can hurt someone if they don't move very much and don't snare you (still talking about tier 2, but i hear it gets much worse in tier 3).
4. Scenarios seem to give the most experience, grinding pq's is also good but not as good.
5. Like the gamespot review says, the questing is mediocre in comparison to pvp, and the pvp is still waiting to be balanced perfectly.
I think all the balancing will get ironed out over time, but I don't know if I'll get over the slow combat, it's personal taste though, so whatever.