I have completed the Jedi Consular, Smuggler and 3/4 the way through Sith Warrior.
Sith Warrior story hands down my favorite. Its the only class story so far in which i actually feel like the iconic character its based on, being Vader. Its very good.
Smuggler is a close second, but its how you play it.
Jedi Consular i did not like very much, it was good, but not my cup of tea.