"I switched to X-Vision after I dropped my Cressi Big Eye overboard (unintentionally)."
My husband made the same switch too, but for different reasons. Primarily because the clear skirt on the Cressi Big Eyes reflected too much while snorkeling & at lower depth. Secondly because the skirt on the Big Eye pushes up on the lower part of the nose too much - just above the lip - and can be rather unfortable. I find that it pushes up so much, it's painful. Mind you my nose has been broken so I'm possibly more sensitive than most.
"The X-Vision may have slightly larger field of vision but I am not sure. "
I switched from more expensive TUSA Splendive to the Mares X- Vision after trying my husband's X- Vision mask. In comparison to the Cressi Big Eye, we haven't noticed much of a difference in terms of field of vision. The field of vision is certainly better than what I had on the TUSA, albeit it's not the model in question. We both find the X-Vision a lot more comfortable than the Big Eyes, probably because it's softer.
"My old Cressi had clear skirt where as my new X-Vision has black skirt so I get a little bit more tunnel vision effect (but better for photography). X-vision pinched my nose a little more but the skirt is softer and more comfortable overall. "
"I think the X-vision tends to leak in water a bit more readily than the Cressi but clearing the mask is very easy."
We haven't noticed a difference in terms of leakage compared to the Big Eye, but it certainly leaks a lot less than the TUSA, which was my primarly reason for switching over.
"I think I would be very happy with either but since I don't have them for side by side comparison, it would be tough to say which one is definitely better. I have not tried the Visualator since I need a mask that I can use prescription lens".
We prefer the X-Vision over the big Eyes and we can compare side by side. The Big Eyes in now our first back up mask, and the TUSA is used as second backup