So pressing the "mute" button gets the BB into standby, while using TMO's magnet case (inserting BB upside down) gets the BB in sleep mode.

What exactly is the functional difference between the two, except for the profile choices (in holster, out of holster). Is there any real difference in what the BB powers off and leaves on? Is there any difference in power savings?

I know that in sleep mode at least my left convenience key still functions. reprogrammed that to be the calcualtor and find it open all the time when I pull the phone out. I haven't tested any thing else.

... it will be interesting to see if anybody knows the answer to this question.. seems basic to me, but no answers in the documentation....

I might be wrong but I thought the Mute/Standby button was designed more for Battery saving. It shuts down the screen and no key turns it on (voice dialing, camera or any other key) however if you call the cell it accepts the call and again if you let the blackberry miss the call it goes back into the standby mode.