1) The PVE is heavily story driven, which is fun and engaging at times, but at its roots, simply tries to mask how linear it is. The amount of side quests varies from world to world, but you essentially needs to do most of them to be the appropriate level for the next world.
2) Pvp is moderately balanced, but the over all flow of combat feels a bit clunky, making it very unenjoyable for me.
3) In conjunction with answer 1... EXTREMELY grindy. It was fun enough for a while. I made to lvl 35 on a Sith Assassin before I finally had my fill and un-subbed.
4) The voice acting is really the main thing they have going for them (in my opinion) in terms of keeping you engaged in the story. The over all stories are well written, and would actually make some decent novels with minimal tweaks. I actually enjoyed having everything spoken to me, versus having to read witty quips, one liners, and pop culture references (albeit I do chuckle at them from time to time)
Over all, I would give SWTOR 7.5 stars out of 10. It (again.. IN MY OPINION) wasn't a horrid game, but after playing WoW for the better part of 6 years, and trying pretty much all new MMOs only to come back to WoW, I feel that I'm simply set in my ways of what I like, and what turns me off.
Some good points*
1) The player base seemed rather large and active (though, the action of actually forming a group and traveling to an instance felt a little alien at first, it was actually quite refreshing
2) The armor and weapon artwork stayed very true to the Star Wars brand. I liked it.
3) The worlds are rather large, and its quite some time before you get a speeder, meaning you hoof around quite a bit and see the vast majority of the terrain.
4) The weapon customization is fairly detailed, in the sense that you can upgrade a weapon multiple times to keep it competitive. I was able to use the same double bladed light saber for 8 levels before I needed an upgrade, and only had to spend small amounts of credits to keep it up and going. (That and the color crystals are pretty awesome too, you can even change the color of your blaster bolts)
5) Space combat missions were fun. Granted, they did get a bit stale when I hadn't unlocked new ones, but they have daily quests that award a pretty decent chunk of exp around the low to mid levels.
Were it not for being an avid and frequent WoW player, I would most likely still continue pressing on in that galaxy far far away.