Well,
Our first live event went well with the IEM's. It was a rough start, but after some tweaking during rehearsal, things started to fall into place. I only had 2 real problems.
With the other guitarist, he had phones that had no isolation. He was telling me how he could hear the house while he is 20 feet behind em with phones on. I tried them on and noticed that I could still clearly hear every word someone next to me was saying in a conversation with someone else... even had great diction. LOL

I will probably buy him a pair of REAL phones.
I was using the low end shure PSM200 system and it compresses way too easy. I think after another week or 2 it will be worked out to a science.
All in all, I would never go back.