My only back to back same day experience was with a rkt 858 kit and a Silber turbo'd pro with a low comp. head on 8 psi with av gas in it (not the best for throttle response) at roughly 1500'-2000'. Right out of the hole from a dead stop the bb felt stronger, but if you wick the throttle on the turbo to keep boost up while riding the difference in response became negligible. On the mid to top end the Bb wasn't even close.
Turbos require more maintenance (with the exception of some BB's I've ridden with in the past), especially when you get to the higher boost set ups. However IMO they have more gain per dollar spent and have a bigger fun factor.