Funny you ask, because a buddy of mine was actually on the M:I6 set for a day a few weeks ago in Paris and was echoing basically everything you're saying. I'd rather not get into details, because of why my buddy was on set - if you've read a couple of my other fairly recent, Pirates-related posts, you can probably connect the dots - but yeah, he said it was a sight to behold to witness Cruise in action, both in front of the camera and especially when the cameras weren't rolling. Said he's basically more in charge than even the director, and is just constantly motivating the crew, never leaves the set to go to his trailer (which is super rare), and is just an all around hard working, super nice bad ass. I've heard that from so many people over the years, and it really is true.
Another good friend worked for Cruise/Wagner - Cruise's old production company with producing partner Paula Wagner - years and years ago, before I knew him, and has one of my favorite stories ever that we still joke about to this day. It's super simple, but, basically, Tom was never really around the office, so my buddy only had a handful of interactions with him over the couple years he worked there, and when he finally left he asked Cruise's assistant to have Tom sign a poster for him. I can't remember which poster it was, but my buddy's name is Dan, and all Tom wrote on the poster was:
Dan,
Tom Cruise
I don't know why, but that cracks me up so much. No little extra note or message or thank you or anything. When we're all hanging out, sometimes I'll just look over at Dan and say, "Dan, comma... Tom Cruise." And it just never gets old. A little inside-jokish, I know, but it's so perfect.