Even though it looks like you've already made your decision, I'm gonna jump in here and recommend the Sigma ROX 5.0 wireless bike computer.

I've been using mine for almost 2 years, and I've only needed to replace the battery in the head unit once. Just recently, in fact. The batteries in the speed sensor, cadence sensor and HRM are still the originals that came with the system.

Overall, this bike computer has been utterly reliable for me, and is definitely worth considering.