In 2006 the made in Mexico start was up graded with extra large frets a shielded pickgaurd and a thicker tremolo block. (I believe the larger tremolo block was recently made standard this year in American strats. There's a guitar store in Clearwater, Florida where they have just about every model Fender makes aside from special orders. If you going to keep the original pickups or especialy like the american saddles or absolutly need that 22 fret get an American. Otherwise if your going to chang the pickup and don't need the 22 fret there isn't that much different. I have an American Highway fat stat with a Duncan Jeff Beck, a special Edition ash start that I installed a hot rail in and a $400 dollar Mexican fat start I installed a Duncan Screamin' Demon also with the shieled pickgaurg you can get a great Yngwie like tone from the stock front single coil. They all play pretty much the same, but the one with the most tone is by far the Mexican start with the George Lynch Scremin' demon.
I've been playing 30 years and also own 6 Ibanez, 2 Jacksons, 2 Charvels one Schecter and 3 Esp solid body guitars. I do personaly prefer the ESP and Fenders over the others.