Two-bike units? Basic cyclometers are cheap enough that it doesn't make sense to me, especially if you get multiple mounts, pickups, etc.. I had three different ones on three different bikes. Now I'm using a Garmin Edge which doesn't really need pickups, though I do have the wheel and cadence pick-up on two of my bikes.

I find having a clock nice as it can be tough to see my watch when wearing a jacket and winter gloves. Temperature, altitude, gradient, HR, cadence can either add or subtract from your riding experience, depending on your goals and point of view.

One option that may work for you is to use your GPS enabled smart phone with a cyclometer app. There are handlebar mounts for iPhones (and others, I presume) and I've used both the Cyclemeter and B.iCycle apps that worked very well, plus you get a moving map, they record your rides and you can save and view them on your computer, etc.. Cyclemeter just added a feature where you can preplan a route and download it to the phone to follow. Battery life, water resistance, etc are considerations.

These apps will work showing your speed, recording your ride, etc. without data or phone connectivity because they use the GPS receiver in the phone, but the map they display comes down quasi real time so you need connectivity for that.