Here's a boatload of questions for you. What happens if you quit now, do you still have a commitment? Are you working another job right now that you like and pays the bills? You are commuting to drill, so you're not local, that's a pain in the butt, are you going to have to commute there forever, or are you planning to move? Commuting to drill isn't easy, especially if you don't have jumpseat privileges.
Since you really don't know for sure what's going to happen in the future (ie are they going to keep dragging their feet, will the unit shrink, will you make it through UPT, how long will the mega hiring at the airlines last), I suggest you think about what you'd really like to be doing for the next several years.
Do you see yourself enjoying being part of this guard unit and their mission, or is it just a means to an end? Do they get deployed often, and is that appealing or not. Can you go on a trip with them, watch what they do and talk to the pilots, do you see yourself doing that? How about the commuter life, is it for you? Can you start working on the commuter route right now and make the decision before you go to anything that commits you further with the guard?
I never saw myself as anything but a military pilot, and never even planned to get out. It was a no brainer for me. But if you consider that either way, what if you were hired by a major in the same amount of time (because you really don't know), what way would you choose to go, what do you want to spend your life doing?