I also got a chance to beta test SWTOR, taking most classes to level 10, and a couple past 30 (out of 50).
My thoughts:
Positives
To avoid unbalanced queueing, they've introduced a PvP Warzone - think battlegrounds in WoW - where same-faction groups are pitted against each other.
An innovative "Powering Up" system that boosts the stats of lower level players in Warzones. It sounds daft, but this worked quite well.
The core gameplay and mechanics are solid, if buggy, but far more polished than any other MMO I've "beta'd" (N.B. quite a few).
An initially confusing crafting system that actually turns out to be quite intuitive and functional.
Levelling up seems paced quite nicely.
The game will launch with PvE raids in place.
Negatives
An over-emphasis (and overspend imo) on the voice acting and storytelling aspect of the game. In my view, you write your own 'story' in an MMO through your actions and experiences, alone or with friends/guildies/random pugs.
Very little information about life at max level.
A strong presence of fanboys and trolls on the community forums.
And the rest?
To be fair to the game, everything else is average fare for an MMO. What will make or break SWTOR is how quickly they add new content and address issues with future patches, as well as how they handle their customers (always a concern when EA are involved).
Oh, and it plays almost exactly like WoW, except with a Star Wars skin. It's up to the individual whether this is a good or bad thing. Whilst I liked that, for example, my Sage played almost exactly like a WoW priest - similar talents and spells but with a different name - I was hoping for something a little more. If you're going to make a WoW clone, you should probably make more effort to improve upon the original.
I'll likely give it a whirl for a couple of months.