Thanks to everyone for your advice. I'm still mulling it over, but I think rekmayata has the best advice:
Originally Posted by
rekmeyata
I suggest you study on the internet the computers being suggested here to find the one you think you'll like best.
I hadn't seen much of Sigma, but it turns out my LBS carries them. The model you mention - the BC1609 certainly would do everything I need, and more. I'm good with purchasing the second cable/sensor, and fully expected to have to do that. Reliability is the biggest thing - I don't mind changing batteries every year or two, but I don't want to have to switch to another computer + second cable mount + second sensor in a year or two if the computer dies/is no longer made.
Cateye has some models that I'll look at as well, but I'm leaning towards Sigma because they're stocked locally.
Thanks again to all for your advice!