Nunatak has an excellent reputation--I've never seen one as they're not in stores and what store would carry them, anyway?

Coincidentally, I spend last season using a Golite Ultra20 quilt and found it can handle a broad range of conditions, as well as ground and hammock sleeping. I really like the foot box (don't think I'd like a flat quilt) and I got a long, so I can actually cover my head if I need to. The only glitch is the adjustment straps are too thin and fold, making them hard to adjust during the night--they can be easily replaced.

I've had a WM UL for more than a decade and as a flexible, light sleeping bag it's hard to top. It's quite snug so not for everybody--the quilt is probably a better solution for those occasional warm nights.

Good luck!