I've had a couple of wireless in the past and didn't like them at all. I go strictly with wired now. So much so that I passed on the one feature I was really wanting - altitude as that was only on the wireless ones that I found.

I got a wired Planet Bike Protoge 9.0 instead. Works well, no buttons to push after the initial set up (less openings for moisture), fairly heavy wiring at about 1/8 in thick. I'm happy with it.

I had the additional issue (with any computer) of trying to get it to work on a recumbent tadpole trike.... no real place to put the sensor close to the spoke magnet. Got this http://www.rei.com/product/736957 - the pic on the web page is like 4 times the actual size - and you can have up to a 20mm gap between the sensor and the magnet.