I know this isn't what you are looking for, but I ride w a polar Fs2.
No cyclocomputer, (just HRM), no time spent in x zone, just avg, max and current HR.
It's very reliable and the one I own right now has lasted a year and a half w/o problems. I just bought a new one in case and so that I can give my old one to a new rider on the intercollegiate team next semester.
Why do you want a cyclocomputer anyway???? All that matters for training purposes is time and a way to monitor your effort. Whether you rode in zone2 for 3 hours at 14mph on a mountainous route or 18 mph on a flat course doesn't make much of a difference provided you rode in the same zone.
I used to use a cyclocomputer but it said "You SUCK" everytime I checked the speed. I no longer need a computer to confirm that.
If you are THAT concerned about your mileage/avg speed you can mapmyride it.