Worked for me on my EVO with CM6. For me it basically just skipped the splash screen and booted straight from the boot animation. It was definitely quicker.
Now what are the +\- of using this versus just doing a normal reboot? Pretty much what does a normal reboot provide us that this cant?
On the galaxy S it is 2 times as fast as a normal reboot (clocked: 19s. hot reboot, 43s. normal reboot) Don't know about the EVO CM6.
+ is that one can kill all tasks at once and start with a clean system (snapier)
+ if one has to reboot because of a change: faster
+ beautiful reboot animation
- the system isn't totally reinitialised from the start (properties from build.prop aren't reset), but then again why does it have to?
- don't know yet.
I see it as a fast task killer, system memory cleaner and a handy, fast reboot option if changing something requires that.