Is there already a shmup thread? I couldn't find one. If so, please delete/combine so I don't clutter up the boards.
Sine Mora, the new bullet-hell shmup on the XBLA, is pretty good. It doesn't have the ultra-polished feel of a classic Cave shmup. Everything is a bit too fast, and I don't feel as though I have a good grasp on where my hit-box is; this is especially true since you change ships frequently, thus you don't have the time to get used to the hit-box. I also feel as though the controls are just ever so overly touchy.
The bullet patterns are pretty good, but again I think they're a little fast, and so the game relies too much on the speed-up mechanic. I think the bullets are a little small as well - in this regard the game is far more like the Raizing/Eighting shmups than it is the Cave stuff, and while I liked some of their games (Armed Police Batrider), I always preferred Cave's stuff.
I do like that there are environmental dangers, but the levels so far are not as well-designed as R-Type Delta's are.