I've been on Betaseron for 13+ years, now.
Yes, they do offer an autoinjector. I tried it and found it pretty cumbersome, clumsy...but others find it real useful, so you'd probably have to try it for yourself and see what works best for you.
Without the autoinjector, the needle really is small -- the same size needles diabetics use to inject themselves several times a day, sometimes...and we only do it once every other day.
Most people do experience significant side effects -- what they talk about as "flu-like" -- for the first couple of months, and then it tapers off. But it really isn't all that awful -- careful preparation with ibuprofen (or tylenol or something similar) before injection, then again the next day, usually gets you through it. I was working full time at a job that required my driving around the state when I started it..and never missed any work because of it.
The Betaseron company is pretty helpful for new patients, offering training, and 24 hour nurse access, should you have questions or problems.
And you can always ask here; we'll try to help..