There's pros and cons to both, it just depends on what you want. A Wireless job looks nicer when it's on the bike due to no wire going from the computer to the sender, but they cost more to get the same features found in a wired computer. Wireless computers use batteries in the computer and sender, the bat in the wireless computer will last at least 5 years same with wired, the wireless sender about 6 months. The wireless is a bit heavier due to the bulky sending unit. Typically a wireless computer will last about 4 years though none of mine ever made it past 3 years. Overall I believe wired computers are better in terms of features, reliability, and cost.

Brand wise Cateye and Sigma are my favorites, currently I use Sigma's, I think they offer more features for the money, plus I think their the nicest looking of all the computers on the market.