I have a Garmin 310xt and use the cadence sensor with it.
Prior to that I had a specialized wireless sport computer and used it with a Reebok HRM. No problems.
I got the Garmin because I found out that I have a congenital heart condition and was told to watch my exertion levels. The 310 xt will do vibrating alerts. I really like that on group rides so my HR alert isn't being broadcast to everyone around me.
2008 Specialized TriCross | Selle Italia Diva Gel Flow
2009 Trek Madone 5.2 (WSD) | Terry Falcon X