NCDIH,
As others have stated, most of us have second guessed our decision as well. I had scheduled microsurgery, then cancelled it in favor of GK for some of the same reasons you are questioning it. My gut favored microsurgery, but my engineering background forced me to sift through the data in favor of GK. After further probing the various physicians about my specific situation (e.g. tumor location, size, etc.), I then had better data that showed a similar outcome (e.g. facial nerve preservation, balance issues, headaches, etc.) between both GK and microsurgery for tumors 2cm or smaller. This was what I needed to change my mind back to microsurgery, since it matched my gut feeling and addressed the open concerns I had.
It is now just over 7 weeks post surgery (I had translab as opposed to retrosigmoid) and my recovery has been very fast and uneventful. Although it was very stressful on the front end, I am glad to have chosen microsurgery so far.
My suggestion is to find what is needed to address your open concerns. In reality, both microsurgery and radiosurgery have very good results, especially for smaller tumors like yours. You will always see worse stories out there from microsurgery, since many patients treated by this method have very large tumors or in very dangerous locations that could not even be treated by radiosurgery. I had to keep reminding myself of this as well.
I wish you the best with your decision and outcome.