Well my experience was two fold but some was unexpected and some wasn't.
So basically the engine is very very poorly optimised. I was getting around 30-40% GPU usage across both of my cards and around 300-500mb of memory usage and achieving at times 20 fps up to 40 fps, this was also with the game maxed out and using 2x 1gb GTX 460's. This worries me considering a lot of people say its "ready for release", but then we've had SWTOR with there poorly optimised engine as well, seems its acceptable for a MMO to be released with a poorly optimised engines.
The combat was interesting, but sadly i can see it becoming quite dull. I played a Necro for a couple of levels unlocking all the skills linked to the Dagger, Axe, Staff, Horn and Cow Bell. It seems they always give you 1 auto attack, 1 other attack and then they mix it up with controls and aoe's, and these skills don't change ever. Then i played a warrior for a bit, unlocked all skills for the 1h sword and shield and this was probably the most boring time I've had with a MMO to date. Compared to TERA the combat is shocking, TERA's combat is probably the best combat ever created in a MMO. Pure Player Skill.
The questing system to me felt like MASSIVE zergs, it was a race to get to content before the event completed to get your XP. Then when i arrived at places already done, i just stood around for minutes (up to 10mins) waiting for content to start so i could start levelling again. This to me was VERY immersion breaking, i don't want to be waiting for my content to come to me, i want to be able to consume at my own pace and sadly this game does not offer me this. Also the dynamic events, because they are so liberally used seem more like survival waves rather then questing/content, kill mobs until the bar fills, collect item until the bar fills, do x until y triggers and repeat. Rift actually did a better job in this regard because they included the dynamic events with questing, giving you a choice of content to consume at your own pace and then being offered more content at random times.
Something about the strafing movement is really weird compared to all other MMO's.
Overall my experience from a very short time was incredibly poor. I still have the game purchased and i'll give it a ago again at some point, but from this i felt the game did not live up to any of its hype. And i could never see this being a full time MMO for me.