There are some "extras" in the Vision which I miss greatly when in an XRS - but it is mainly a Collins (Vision) vs Honeywell (XRS) thing.
Good Vision features:
- Flight plan amendments previewed and then EXECUTED
- Visual (on-screen) fixes for pilot selectable waypoints/ETPs/etc and range rings available (great for diverts/ETPs/circling areas)
- Off-track VNAV
Obviously, with the screen "real-estate" the Vision is a HELL of a lot nicer than the XRS, but there's not too many FMS differences. I am biased towards the Collins way of doing things, though I've met many who prefer the Honeywell way of doing things...