The W800i I have kept losing service where I am. When it did, I would throw my sim into a Motorola or Nokia and they worked just fine. I lent the W800 to some co-workers and they were quick to hand it back. The general consensus was it had poor RF. Your reception may vary based on your tower location, geographic topography, atmospheric conditions, indoors/outdoors, etc. The W800 is tri-band (900/1800/1900). Since T-Mobile is only 1900 it works fine with their network.
Personally, I got my hands on a ROKR and I refuse to part with it (for the time being). The RF is awesome and while it won't hold as many songs as the W800 (100 vs. ~120), it's good enough for me. The L7 I saw has iTunes (and Apple's 100 song limitation). I'm not sure about the RF though. Looks like Cingular is picking it up in their lineup (http://www.phonearena.com/htmls/Motorola-L7-SLVR-V8-phone-p_1118.html). If that's true it's going to have good RF. They are real particular about that.
Tango Uniform.