It’s all personal preference. I have owned all three and I kept the Ventris - the only thing I hate is having the connections on the side and not the back. I really love the actual MIDI connector and the options for programming with the app or the computer - TONS of options inside the box. I expect that I will wind up with a Big Sky again - lots of the same style reverbs but the pedals are like cinnamon and nutmeg - both make egg nog great, but you may prefer one over the other.
I think the Empress sounded more subtle and very natural, but I was looking for more character and options. I would rank the reverb pedals in this order (for me) Ventris, BigSky, Empress, H9, HX Stomp. The other pedal that I am curious about is the Specular Tempus (Reverb and Delay).
Also, as a bonus, there is the Source Audio Collider which is half of the Ventris and half of the Nemesis (delay) all in one pedal.