I was very apprehensive about starting Rebif, but all in all everything was okay. I had very few side effects---always premedicated, still do, but I only take 1 Advil.
I've been on it over a year and now shot nights are just part of my routine.
Some people have flu like symptoms, which usually lessen over time.
Best of all, my latest MRI showed no new lesions.
Best of luck on your decision.