I'm on 'butrin, and it was initially helpful. It brought my scary, sui depression down to a moderate depression, dropping my Beck Depression Inventory score by 10 points! But it hasn't been a good maintenance drug for me; it allowed me to get very (though not quite as badly) depressed a few months ago.
Everyone reacts differently to it. I personally have had no sleep problems. I also have not had any decrease in appetite related to Wellbutrin. (Ironically enough, I did have a decrease in appetite related to the depression that Wellbutrin didn't prevent and lost eight pounds).
My doctor recently added Lexapro, an SSRI, to my mix. I am starting to finally fully recover from my depression. In fact, I'm starting to feel a bit hypomanic, which is a darn good thing.
I hope that Wellbutrin works better for you than it has for me.