Having lived with both I prefer the xr1100... I was tempted by all the xr1000s on offer as end of line, but the difference was very noticable. The much bigger visor area, bigger pinlock and noise difference is what I was sold on.
The xr1100 is a completely different shape and entirely new design. Sit them next to each other on the worktop and the difference is very noticable. The shop was probably trying to get rid of old xr1000 stock and earned an incentive for selling one.
Edit:
http://www.youtube.com/watch?v=BXarU...=youtube_gdata
good little you tube video showing a run down of the helmet. Show the difference in visor/pinlock size which was my biggest annoyance with the 1000. The visor seemed tony and the pinlock line was right across your eyeline when tucked in behind the screen or cranked over.