Originally Posted by TechniSol
You'll find it charges much more quickly with the higher output charger, the 9W model... 1.8Amps vs. 850ma. for the other.
Interestingly, Amazon claims otherwise for their e-ink
"Optimized for Kindle tablets: PowerFast is a 9W charger and will charge your Kindle tablets faster than the white 5W Kindle charger will. (Note Kindle e-readers will charge at the same rate regardless of if you use a 5W or 9W charger)"