I recently traded in my 916 for a 2005 R1 (but I'm keeping the SP3). I chose the R1 over a ZX10 mainly because it is a bit roomier, and I doubt I'd tell the difference in performance etc, they're both far better than I can really use! There's obviously a vast difference in performance, and they both handle well (to me), but in different ways if that makes sense. I basically bought the R1 because I had to get that performance thing out of my system, and I've no regrets at all so far.
Andrew