After comparing frequency charts and distances, (and price!) I chose to get the Shure PSM300 over the 900(and, as a side note, I've since a/b'd the two systems side by side), and I've been thoroughly happy with the choice. I was already using the Shure ULXD4 for my guitar wireless, and was thoroughly impressed as well, and had a few extra SB900 batteries which seem to last forever, and I had a charger set up at each gig, so now I can use it/them for both setups..... I've never had a signal dropout, great sound, no delay, love them.
I might invest in nicer in-earns at one point, the psm300 came with 215's, I might, at some point get some fancy ultimate ears or shure 545's or something...
I also just bought a thing I saw online, not sure if anyone else has seen or tried it yet - www,rev33.com it clips onto your existing in ear system and apparently makes it sound better. It was only $99, so I thought I'd try it and see what it does. It's due to arrive this week, I'll let you know what it sounds like/does when I get it.....they say it reduces ear fatigue and eliminates distortion in your headphones,,,,
