I'm not as talented in expressing technicalities of optics and how they differ, but I owned the 10x42 SV and 10x50SV at the same time. I found the 10x42SV to be the best of that configuration that I had ever used. There is something special about the 10x50 though that makes it superior to my 55 yr old eyes. The immersive view (as mentioned), the view that makes you feel like you are in the picture, not looking at it, almost a 3D like view if possible in a roof. All of that makes the 10x50SV the finest glass I've ever seen, used, owned, etc and I've been fortunate to see most of the high end stuff.
That being said, if you don't have them side by side I doubt you'll ever know what your missing. I could happily hunt with a 10x42 SV and never look back. Mount those 10x50's on a tripod though......WOW!