well, i've never tested mine against a real quality thermometer, but...

* my Cateye seems to often be quite wrong - the temperature just seems way off - like it'll say +5C when it's snowing and the predicted high for the day is -1C.
* my Specialized pro i used to have (fell off and got lost on a steep descent Fall 2001) seemed to be pretty much right
* my Ciclo (414M?) seems to always be right on

so i think there is some major variance in the quality of the temperature readings which makes sense since it's an "extra" feature often just added on to increase the list of functions...

also on the elevation and the elevation gained measurements, my Cateye is just worthless (for instance i haven't calibrated it in weeks and it currently shoes -300m when it should be 510m) while my Ciclo is so unbelievable accurate and reliable i have been amazed -- the values always seem to jive with map values AND when you compare 4 different computers readings for the same trip you get within a few meters (maybe some guy rode back a little bit or someone took a detour to relieve himself or check out a view...) --- it often seems to be much more accurate than my expensive mountaineering Sunto altimeter - especially in counting vertical ascent/descent.

needless to say, i am QUITE satisfied with the Ciclo... although i'm not sure how common they are out of Europe. in Germany it is pretty much the TOP computer - they make HRMs too but i've no experience with them. the major complaint about Ciclos seems to be that they have SO many functions that they can be hard to use. my Ciclo doesn't have as many functions as others (some have ski-speed and HR and many more averages, maxes than the basic ones i have) although it has all i need (2 wheel settings, min/max/average for most values, plus computer interface to download all my data)

if i think about it, sometime i'll run a temperature reading test between my Ciclo and my Sunto (top mountaineering altimeter with temperature) on my next tour...