I had a blast with it, and was surprised. It still remains a somewhat B-grade shooter, but it's fun nonetheless.
Normally I don't like seeing shooters with gimmicks, but Jericho actually has a nice amount of refreshing innovations.
Play it on Windows if you can, though, the game feels much weaker on consoles. The PS3 demo is particularly bad since in it the game isn't optimized yet and has a resolution that's closer to SDTV than HDTV, IIRC. It's full of jaggies and shit.
Contrastingly, Timeshit is everything that you could possibly hate about gimmick-based FPS'es. Urgh.