Lutron Maestro IR (Model MIR-600THW-WH). I installed it this morning and it works well. It is a little finicky when I try to use it with my MX-800 remote. That remote works via RF, converts the RF to IR, and then sends the IR back out to 6 emitters that you can hide around the room to hit the components you need it to without actually aiming at anything...
Anyway, strangely, it works just fine when using IR from the MX-800 only, but when I try to use the RF function and have it emitted on the add-on emitters, it doesn't work unless the emitter is within 3 feet of the 'eye' on the wall switch. I googled it and found out that the bands of frequencies it accepts are apparently very narrow so you might have problems with some learning remotes.
In the end, it works fine with just the IR setting on my remote, so I'm keeping it and will try to put the rest of the mysterious behavior out of my mind.
It is the coolest $40 addition I can imagine making to my Home Theater.... I'm very happy with it.