Depends if you are going racing or riding on the streets. On the test I read, the 05 has nothing below 6,000 rpm, so not much fun on the streets. I assume the 06 is the same.
Before 1999, all the 600's were streetbikes first, and racers second. The R6 changed all that, and the other manufacturers soon followed. And carbed bikes are just as good, if not better than fuel injected.