Both my BF and I have the Sigma 1606 L. We had wireless at first but switched them back to wired because our heart rate monitor would interfer with the wireless systems. Plus, I can't use my bike light with it neither (Light and Motion Arc). I like the Sigma because we both have 2 bikes and the Sigma can store 2 bikes' data.

Personally, I would love to have a wireless system. But unless I buy a digitally encoded wireless system (which is expensive), I would rather have the wire and save some money.