My quick couple hours with it review. A lot of my opinions will be obvious probably but it is what it is, so here goes...
Playing bigsky mx in single mode with each algorithm is pretty similar to original bigsky, except perhaps a brighter, more polished hi-fi sound from what I remember. I don't have original next too it to compare and only going off memory. Maybe due to different processor etc.
Playing bigsky mx in dual mode is where the fun begins. Mixing algorithms in series, parallel, split etc. That is where I think most people will find the comfort zone to be honest and obviously the reason for this newer version. Pairing Cloud up with Magneto or Bloom and Cloud together or Chorale and Plate. Lowering one in the mix with small decay and let the other one be little louder in the mix but with the decay longer to carry both etc.
Convolution reverbs are fun too! I've been messing with some of mine and I obviously like the more weird ones and yet it gets more weirder when playing with the controls like attack, stretch, reverse and modulation, then pairing that up with another weird IR or algorithm reverb is super fun!
I really like infinite mode. Don't care for freeze mode to be honest. I'll park my happy little butt on infinite mode for everything, and it makes all the algorithm reverbs and convolution reverbs more fun in my opinion.
With all of that said, for anyone still wanting Mercury X, don't sleep on it. I was playing it back and forth between bigsky and it and it's definitely different in a good way and if you're looking to get more strange and more weird stuff along with normal too then Mercury X is where it's at since it's a modular platform and you can pretty much make your own reverb with the tools in it.
I didn't check it against my H90's, but that's another one that is great with normal and has some weirdness too and definitely different flavor compared in tones / sound compared to mercury x and bigsky mx, but H90 can do dual reverbs too so you can get more strange / weird if needed.
The end result? GET ALL THE REVERBS :)