Joe, I think you've summed it up pretty well, yep.
Where Monster Manuals should excel is in terrific beasties that inspires the GM and makes them think "I could use this!" every time they turn the page. The Monsternomicon is a work of art in this respect; it's probably the bestest bestiary ever written for sheer monster goodness. The Tome(s) of Horror come close, bolstered by their nostalic tear-inducing value. I have, and use them all.
MMIV contains pretty good monsters - on a par with MMIII, certainly - but in a format that's easier for a GM to use. I like that there are themes to some critters too - it adds consistency into the gameworld, if you want it. I've used it more than any other MM after the first, so for value for money, it's a winner.
As you said, it's great for begninning GMs too. All good stuff.
Provided the monsters are of a high quality, I'm glad MMV looks like being more of the same.