I use the B lot all the time. The staff is great and helpful. It's a heck of a lot cheaper than the Airport PArking Garage.
The longest I've ever had to wait for a shuttle was 20 minutes. And that's only after using them extensively for 4 year. The longest I ever had to wait at the lot it self was about 30 minutes on that same night, so they must have been having a bad day.
The vast majority of the time I'm on the bus in less than 5 minutes and my car is waiting for me when I get to the lot.
Now things may be different at the garage (lot G) but the folks at Lot B are awesome.
Cromely.