I have a pair of the Sennheiser wireless headphones, but being wireless means that they have to use limiters and radio.
You know how different stuff sound on radio compared to a record or CD? Same with wireless headphones. A lot of detail is obscured.
The Sennheisers aren't harsh, and wireless headphones are often useful for general use in the studio when I don't want to be tethered to a cable, but they're not the same as a good pair of wired phones.
I've never heard of infared ones, so you're one up on me.
Limiters are similar to compressors. The problem is that RF transmission is a problem for very soft and very loud sounds, so the transmitters tend to use them so that these sounds can be transmitted easily.
Remember that with RF headphones, we aren't talking about very costly radio transmitters, so the fidelity has to be a little compromised.
However, I do find them useful for those times when I'm running around the studio setting up mics, back and forth into the control room, etc. Also, they're nice for general hi fi listening when I don't want to disturb anyone.