Are you guys rooted and using the latest radio, or tried different ones? Probably has a lot to do with location, but the only time I ever lose 4G is when I go into the metal enclosures at work and shut the door. I never use wifi or 3G either though, LTE 24/7.
im actulaly running unrooted after having run the rooted for several months.
the latest semi official cyanogen build still crahes with some things. like google talk has constant FCs.
as much as people love cyanogen mod and i'm thankful for them with some of the other phones i've had that never had support (like the g1 past 1.6 etc), these roms are a lot flakier than some of the carrier tested images. like the current 2.3.4 htc sense build seems very solid, and it feels faster than CM 7.1.1 .
i suppose for me CM is only worth it if you really hate the skin and if your phone is not up to the current version of android. once HTC had gingerbread i went back to stock as CM7.1.1 for tbolt i still don't think is nearly as solid. you get weird freezes sometimes it doesnt reboot right, etc.