I bought an OXBUILT dolly about a month ago and I thought I'd pass along my experience. I have a one car garage and was having trouble getting my bike and my car in at the same time. I was pushing the bike up into the far right corner. With the bike on the center stand I could just get my car past and into the garage. Using the dolly I actually have a little more room. The real benefit is in moving the bike around. It is way easier to push the bike to where it needs to go.
When I don't put the car in the garage I use the dolly to turn the bike around. I just ride in onto the dolly and swing it around. I still have to do a little maneuvering but not much. The bike goes from facing in to facing out with relatively little effort.
This is a very sturdy product but not cheap. It cost $300 plus $30 for shipping.
I highly recommend this product to those of you who are hurting for space or are having trouble moving your B in a small garage.