You won't hear many positive things of SW:TOR on this forum, most here are playing WoW and have biased opinions.
SW:TOR is a great game, there are 8 classes that all have their own unique story with 200+ hours of content (granted you'll be doing the same non-class related quests if you make an alt on the same faction).
If you like WoW and/or Bioware games you'll probably also like this game. It has some baby illnesses but it's nothing that won't be remedied in time.
Main difference between TOR and WoW is the story/lore, quality and amount of voice acting and the sci-fi setting instead of a medieval high-fantasy one.