Wired vs wireless is a great debate, personally I like wired because they last longer, and the wireless sending unit fries batteries about every 6 to 9 months thus you need to carry one in your seat bag just in case it goes out on a ride. I've had 3 wireless over the years and none lasted more then 4 years, whereas my previous wired job before the great wireless experiment lasted 25 years! HOWEVER, having said that I just bought a wireless that will go on my new bike! Why? because it was a $259 HRM/bike computer for $45, I decided what the heck, and it can be worn as a watch so when the sending unit fries I'll just wear the thing! It can still be used as a HRM watch just not as a bike computer when that happens.
Overall wired are more durable, they give you more features, and they cost less then wireless.