Good luck with your decision. I used to use prednisone on an off for really bad flares but eventually it stopped working for me. I went on Imuran and it has really helped me. No side effects whatsoever. It took about 1 month for it to kick in. No problems with the blood work as well. It has put me into remission for about the last 2-3 years. So far so good. It's not for everyone but I would definitely consider it since I have had nothing but good experiences with it. If you have any specific questions let me know.
MyUC