* "find ... -delete" probably just calls unlink, just as rm does, which is a libc feature. No subshell spawned thus lean and fast.
* "find ... -exec 'rm {}'" allows to run a command without xargs, but does not allows you to filter and transform the stream. Propably will spawn a subshell for each call.
* "find ... -print0 | sed 'bar' | grep -v foo | frobznicate qux | xargs -0 rm --" is where the power lies. A few more subshells created.
This, to me, shows that 'find' actually does what it should do, and allows you to choose the best way you can do it WRT the task at hand.
