Will a wifi-only Kindle update whispersync automatically as soon as it's in range of a known network? If I am reading in the park where the Kindle can't sync and then walk home will it sync automatically when I get home or do I have to wake it up to get it to sync? I want a Kindle 4, but if syncing isn't totally seamless I may opt for a 3G Touch. I've always had 3G and would hate to have to start thinking about syncing my devices.
It has been my experience with my Basic Kindle (K4) that it does sync fairly quickly after coming back in range of WiFi. Taking into consideration, of course, the time it takes to find the network. I tend to turn WiFi off if I know I'm going to be out of range for an extended period. . .don't see any reason in having it on so that the device keeps looking for a connection it will never find. Then when I get home and turn it back on it generally downloads any outstanding content within a minute or two. Or I can force a sync if I can't wait that long.

It is marginally faster if I never turned WiFi off. . . .