Bummer - sucks when the season ends before it begins, eh?
I had my ACL replaced in August with the hamstring graft. If I were to do it over again, I'd go with the allograft instead because of the quicker recovery time. As you mentioned, there's the ever-so-slight chance of infection or your body rejecting the foreign tissue, but my doctor pointed out that the donor graft tends to stretch less, and the operation for an allograft is less invasive. I believe it is the better choice as long as your doctor is experienced in that type of replacement.
Best of luck to you.