Hi Erin,
I'm on Imuran (well, the generic version Azathioprine) and take 150mg a day. I haven't had ANY negative side effects from it. It took about 7 months to notice any results though and I still experience weakness at times so it hasn't sent me into a medically-controlled remission or anything. I'm also still on 40 mg of pred every second day. I was trying to reduce further but the neuro wasn't happy as some of symptoms were becoming more obvious. The only thing you might want to consider with Imuran is the need for regular blood tests -I know how much you hate your needles! At first I had to go every week, then monthly and now (after a year) I'm down to once every three months. Thankfully all my blood work has been normal! Good luck with whatever you decide!
~Kathy