Spent all day reading this. What's great about the What if? comics is the entire ensemble of Marvel is up for grabs, so if you don't like the tone and characters in one story, you might like the next one. It's a comic where writers are free to do pretty much whatever they want with no repercussions. Because What if? stories have no effect on the "real" Marvel universe, they are almost always epic in scope AND PEOPLE DIE! Also, they can end as downers, and how great is that?
I didn't like a lot of the art in here, although I did appreciate the mimicking of Ditko's art for the Spider-Man tale. I must be hormonal because "What if Susan Richards Died in Childbirth?" and "What if the Hulk Went Berserk?" made me tear up a bit.
The best story by far, though, is What If? #44, "What if Captain America Were Not Revived Until Today?", the today in question being 1983. You can find a more complete synopsis and "reading" of this story on the web, but suffice to say it's a paranoid (?) and heavy-handed left-wing rant against some pretty present-day tyranny more than worth the initial price of admission ($1.00) and a really fun and intriguing read.