I had the 11 S1000 RR sold it for the 12, 1199 I used the 1199 on the track and decided I liked the S1000 more but still liked the model so I sold the 1199 well...it was almost a straight swap at the dealer and sold my 13 675R for the S1000 and the 1199 for the 899, they will both be used on the track along side my 09 675 track bike.
But to fully answer your question, I was never really happy with the motor on the 1199 its almost too much...the fueling is awful but better with Termi's and the upmap, its sublime in the handling dept but I prefer the way the BMW makes its power the 899 already...(only 65 kilometers) is way kinder to ride and I already know how good it is on the track from the 1199, most of the parts left over from the 1199 will fit on the 899 too...exhaust, rearsets, clipon's, it'll have some BST's too when they become available... most likely the first modification will be front cartridge kit and rear shock, then the wheels, then all the stuff from the 1199.