I've had exellent luck with Xenia.
Seems to be very nitrate tolerant, if not enjoys a bit for stronger growth. Xenia does not like new tanks in my experience and cannot tolerate even slight ammonia or nitrite levels.
In other respects, I've found it a weird critter. In one of my 55's under 110watts of PC is would tolerate about 11 hours of light, and then close up, this being on the bottom of the tank. In one of my 30s, where it's doing very well, it's a lot closer to my 6500k halide and can't seem to get enough light.
Most Xenia have a reddish or brown color, which would seem to indicate heavy colonies of zooxanthellae algae, which might account for it's appetitite for nitrate. It's ability to grow like a mad weed is something to be respected, even though I've always liked the looks of it, and it's easy to frag and sell by placing a small rock against it where it soon 'glues' to.
I've heard some interesting theories that the pulsing motion of Xenia is not to capture oxygen, but to release internal gases as the result of the metabolism of the zooxanthellae inside it.