The MiM strat was what they call the Fender 50's Strat. It is the two tone sunburst color. The only important issue I had with this was the sharp and uneven frets. The rest were just upgrades and tweeks I made just to suit myself.
The American strat I have is the American Deluxe V neck. I play it and love it as is. The only thing i did was put on a custom pickguard. ;)
You are probably right that it being the "deluxe" has something to do with the overall quality as well.
I just remembered a buddy of mine has a MiM Strat and asked him about it. He said it did require a set up and a little adjusting when he bought it but other than that he is happy with it. He said he has noticed some few minor cosmetic blemishes and he did his own sheilding. He also said he was going to put in some new Pups someday.
As I was saying, they are far from crap, but as you grow as a player you are more than likely going to want to upgrade some of the parts and pieces. :)
Laters