I've never used the Kindle basic, but I've read in other threads that it is faster by far. That is sort of odd, but I suppose the features that make the Voyage, and the PW2 what they are use system resources that would account for the difference in speed ?
The only two ereaders I've had hands on experience with are the Voyage and the H20, and with that being my only exposure to an ereader, I cannot see where faster than those is useful.