After a couple of hours of general surfing, I decided to set Camino as my default browser for a few days. It's been a while since I ran it as default (way back in the heady days before Safari reared its brushed metal head, when it was called Chimera), and the reason for doing so is absurdly prosaic: I wanted something ligher than Firefox to render some XML output I'm working with (I'm working with GPS data and generating both GPX and KML snippets, and even when it's not valid XML, the syntax highlighting in source view is very useful).
Besides the lack of Cocoa spell-checking (which is understandable), the one other thing I noticed was that Flash seems to take up a lot of CPU (it might be just a transitive thing, since there appears to be no logical explanation as to why the plugin would behave differently). Maybe it's due to be running on my aging iBook, or some such peculiarity.
So far I'm a happy camper, and heartily recommend it if you don't need all the extra Firefox stuff (although I see myself firing it up soon to use some of the extensions when I start wrapping a GUI around what I'm doing...).