I have a Harbor Freight one it works decent a lot of the guys at my shop have Snap-on ones but the HF has worked well for me have had no problems or inaccuracies with it. Some of the new guys even ask to borrow mine over the other guys. I am thinking of buying the Snap-on one at the pawn shop for $50 though.
I bought the MityVac Kit MV4560 as I rarely need a pressure tester. It works OK, but the vinyl hose fittings are not very good, in fact cheap. I found I needed to readjust and test them a number of times doing a pressure test as they have a tendency to come loose.