Not got one yet as the one I looked at today was a little sketchy on the service history front. But now I know what I want the search can be more focussed and I'm sure the right one will come up for sale.
The main reason I decided on the R6 over the zx6R is that below 8K it felt just as fast as my 4R. The zx6R has way better torque all the way through the rev range and I'm sure it's faster. but my brother and I had mx bikes when we where younger (125 me, him 500 - a 500 MX bike is brutal ) which are gutless until you hit the powerband, the R6 felt the same, so it felt familiar and takes more effort to ride which was the deciding factor.
I'm not really a YT type of person but you never know I might just for some fun