I was afraid of it too. It did clear up any of my symptoms within a week of getting back on it, but my pdoc/lab/pharmacy hadn't learned from kindergarten and couldn't cooperate, so I was sick of only getting it 5 days of the week. Also only certain pharmacies stock it.
The lab thing is more of a pain in the butt especially at the beginning because it is super rare anything pops up. I had to repeat them once when I was sick and had an elevated WBC (as one does when sick).
The weight gain was awful though. If med shyt were competent and there was no weight gain, I'd definitely be on it. Not if I'm gaining weight from a med I'm taking 5 days a week and feeling shytty the other two from not having it though.