I think it is hard to compare reverbs as far as which may be better, worse, deeper, more versatile.... etc. Nebula reverbs are numerous, and some are awesome. But the work-flow is so different since you are working with such a huge library of diverse sampled presets. Some are more space coloration's, or even realistic rooms. East West is a more traditional reverb and is equally useful, just different. I use a very inexpensive but amazing reverb called Valhalla Room, look it up. It actually has replaced most of my other verbs, but I still use a Nebula preset when the sound is right. Basically, if you already own Nebula, use some reverb libraries. There are some amazing 3rd party libraries out there. But don't feel like you need to limit yourself to only 1 or 2 verbs. Reverbs are great tools to keep in the "tool-box", so keep a few around.
I really don't know much about dance music. If you can't find more specific information, perhaps you could start a new thread asking about Nebula reverbs for EDM. I can imagine the emt140 plate, for instance, might be interesting for you: http://vnxtsound.blogspot.com/2010/01/s ... -140s.html
that product is plain convolution, nothing more. I don't know about quality of their irs. Nebula is pretty good for dance reverbs, I suggest to COMBINE reverbs for a dance long tailed reverb: duplicate your track and apply on the second one a completely wet reverb (no dry), for example 300 spartans. Than reverb that track opening an insert new instance of nebula, full wet, for example a pcm 70 with 4 seconds of reverb. You'll have a 8 seconds beautiful and dense tail, very good for trance. Using vnxt in a further insert you get something even more solid and long, very alive