I'm another one who uses and raves about Pitlock.

Actually both my wife and I use them and both of us still have our nice (well, nice for us) wheelsets after several years of leaving our commuters locked up on downtown streets on a daily basis.

BTW, I've tried both the Onguard and the Pitlock and have found the Pitlock to be far superior in terms of ease of use and rust resistance. Also with Pitlock you recieve two keys, but the Onguard (really Pinhead components out of Canada) you get only one. College student + one key = dad with powertools.