Quesh is a very small, very dull planet. Good thing its so short or you'd probably develop lung cancer from the polluition (if your species even has lungs). Because I wondered this: when your class quest tells you to go back to the ship, yes, the class quest on Quesh is over. It is very short and felt quite random to me compared to the rest of the storyline. There was one thing I liked about Quesh. I FINALLY got to see a hutt move on its own. It was totally worth the wait! They scrunch around kinda like slugs, but when they want to move fast they do it while pumping their arms like joggers.
Hoth is like Tatooine 2.0. It is a humongous planet almost completely covered in snow and ice. Hopefully you don't mind the cold because you are going to be here for a while. I spent an entire day roaming around the icy plains. There are tons and tons of quests here, most of them fairly interesting (even if the majority of the Imperial quests involve saving them from starving or freezing to death). Plus, after Hoth you get a new companion!
On a side note, sorry for the short *cough*bad*cough* posts the past few days. I'm just finding the leveling process and story really engaging at the moment and its hard to tear myself away long enough to sit down and write about the game. Hopefully I'll hit a lull and will get to delve more into tanking again soon!