Have installed latest CCleaner 2.17.853 on both of my pc's: Desktop w/XP Sp3 and Laptop w/Vista Sp1. Both machines have had many versions of CCleaner with practical instant launch.
The new 2.17 version takes as long as 10-15 seconds for the CCleaner window to appear!
On the desktop (XP), after the initial wait, future launches (on the same day) are practically instantaneous.
On the laptop (Vista), future launches take as long as the initial,,,,,10-15 seconds.
I too have noticed this version being a bit slower to get going.
And then I also noticed that in full screen mode it takes about .400 of a second to clean everything (but wipe free space feature), then when the window is restored down, it only take .200!