Hi AllanH,
ReMatrix full has become my go-to reverb, replacing Waves IR1. I still really like some of the Waves impulses, but the ability to have multiple impulses loaded all at once, zero latency, and the tweakability of ReMatrix kinda seals the deal for me. A couple of (minor) gripes: the preset organization isn't great (search this forum and you'll see a thread or two about that), and, AFAIK, you can't import IR's from other programs, but other than that I love it.
I've been meaning to take a look at the new Waves H-Verb, and I haven't tried Spaces, but right now I'm pretty much just using ReMatrix, Valhalla, and occasionally the IK CSR stuff.
Let me know if you have questions and I can try to answer them.
Dean