Chris,
I have the Shure PSM200 wireless personal monitor system. I bought it for two reasons.
The first reason is because we practice in a small room and it is loud, and earplugs being earplugs, they protect my ears, but I can only hear a muffled version of the band. And, I get splitting headaches if I don't wear something.
The next reason I wanted them is because I sing a lot of harmony with another band member and our voices sound identical alot, and it is very difficult to tell who is who while we are singing. If I'm off key I'll actually think its him sometimes and vice versa.
Price is the issue that held me back for so long it getting something. That and some bad past experiences with wireless gear. But I found a price that I couldn't pass up. The PSM 200 usually sells for $599 and that is a good price, but I was in VA beach at a local music store(Alpha), and they had the PSM for $499! I don't know if that was an error or that good of a deal, but I have not seen them anywhere under $599. So I got it.
It sounds amazing. The unit has 2 seperate inputs and 2 seperate outputs, with individual level controls on each one. So you can run your bass straight through it and a feed off of the p.a. and get the perfect volume in your ear of the mix, and crank your instrument a little higher to really hear yourself. Both channels also have the Lo and Hi Z dual fittings to accept 1/4 or XLR. Very well thought out.
The only complaint I have about it is that the battery doesn't last an extremely long time, maybe 6 or 8 hours. But thats more than plenty for a gig of course, I'm just speaking of practice nights when I let it go until it dies.
I like the ear pieces that come with the set, but you can buy even higher quality ones seperate. You can even buy different inserts to fit your earpieces(foam, rubber), and replacement inserts very cheap. They feel just like earplugs.
Hope this helps,
Brandon