I'm curious, are there any advantages to using a tree of nested CALayers rather than a tree of nested UIViews for a straight boardgame with little animation? I noticed that Apple's GeekGameBoard sample uses nested CALayers and an open source library I've used in the past, Route Me, also relies on using CALayers directly. Just wondering what the typical scenarios are for choosing one method over the other.

CALayers are just bitmaps that you can move around the screen. UIViews have more to them, being UIResponder subclasses. Speed and memory usage are two reasons to use CALayers over UIViews when you don't need an onscreen object to respond to events.