I run in ear monitors nightly. I have a splitter snake that goes to two ULN-8s and a 2882 made by Metric Halo (mhlabs.com), which is like carrying a 24 input 80 bit digital mixer with eq, compression, gates etc. on each channel. The downside is that the investment is considerable and the learning curve is at least moderately steep, but given that I have 25 years experience as an audio engineer and the gear pays for itself with my location recording business, there is no reason not to do it.
I only really recommend using in ears when you can either do it yourself or have an engineer who is known and trusted. If you are working venues who deal with at least lower level national acts, you should have no trouble.
I love the sound I get with Futuresonic Atrios using their softerwear sleeves. The headphone out on the ULN-8 can drive anything and the overall sound is spectacular. In fact, I much preferred the bass sound I got with my in ears to any amp I've been using until I got my fEarful setup. It's that good.
The cheap stuff, not so much.
As far as giving the FOH a stereo channel, I advise against it. No matter how good your in ears and how good their isolation, your mix will always be a compromise for them. They will bring it up, shrug their shoulders and let it suck if it does. Which it well might. I'd at least work out a way to give them submixes: kick, the rest of the drums, bass, vocals, guitars, keys, you get the picture. If you give him no control and act as if he's a more of a problem than a solution, no matter how subtly, he will be even more of a problem. The soundman is your friend, so even if there are issues, act as if he is. An incompetent soundman has nothing on a pissed off soundman when it comes to really screwing things up.
Just my 02c from long experience.
