I had a heated front screen on my Mondeo, and the XJR has one as well, my X-Type not.
TBH it's one of those things, you can live without it if you don't have one, but it's nice to have on those 3 or 4 times a year when you actually need it, and the rest of the time it's a PITA when driving at night.
Ironic never had heated screen on my AWD X Type and could have done with it and made use of it many times,yet my X350 comes with heated screen,seats etc but you cant drive the car on (snow) days bad enough to need it!
We find Heated front screens are absolutely brilliant, even have one on our second car a 1999 Fiesta Skip. When frosty will clear screen whilst your scraping side windows. Night vision I have never noticed a problem but then have had them for so long may not notice it. As others have said, you can live without them.