Eh, I've looked at 4 and 2, and I myself can't justify them. Plus I've never seen a reason to need detail that close. As for the speed, yeah, it does the job alright when it's tracking as you're going down the road. It's when it's being dragged by hand that it's a bit slow because it can't anticipate the next series of tiles and thus preload them.
On a small side note, here's a bit of fun to have with Google Maps. If you've got one of those big painter plotters, what you ought to do is setup a webpage with all the tiles for a given zoom level done in either a big square, or a rectangle, and then use the plotter to print out the map as one humongous sheet. You can then hang it on the wall for people to see and use. It's really kind of neat.
