I've never had any boot issues, but I'll install it anyway.

More than likely, this is to add features/capabilities for a future release of something.

They gave a warning that the fan would go to full speed, I think this firmware was meant for cleaning out any dust that may have got into our Mac's. Gosh apple thinks of everything

I tried installing on my 17 inch MBP and it said this computer does not need this update ...must only be for 15 inch MBP

WOW, I've noticed a definite difference what booting, restarting and shutting down!!

(1) Restarting now is 30 seconds flat on my 1.83 Core Duo iMac.
(2) Shutdown is now 5 seconds flat, everytime

What does SMC stand for?

Edit: "System Management Control" apparently

People over at MacRumors are reporting that apparently the "stealth" fix in this SMC update is that the fans now stay on all the time. This fixes two issues:

1) The MacBook Pro "moo" which was caused by the noise of the fans starting up.

2) Heat issues, reports have MacBook Pros now running several degrees cooler, presumably due to the extra airflow.

Of course, it does mean a noisier machine, but not too bad.

Nothing like the fans while installing, I think my mini actually moved across the desk a bit when those jets started roaring.