I haven't played that many Mexican and American strats to be able to give you a detailed difference. From what I've heard there is a quality difference but in reality the Mexican's are still a really good guitar.
Unfortunately with Fender it really depends where and when it was made and from what line. For instance I played a Mexican 57 Re-issue strat and the fretboard was fat and glossy but sticky. But I have also played a modern 2004 Mexican Tele with the thinner neck that plays almost like the American Tele. I would say that with the Fender the two biggest things that make a difference are the pickups and the fretboards, and since the stock pickups on modern Fender's are all machine factory wound I would venture a guess that the Mexican pickups aren't that much inferior to the American ones. The second item would be the fretboard and the Mexican ones are still good.
Judging from the price they seem to be either Mexican or Corona guitars, my money would be on these guitars being Mexican.
In short on the American vs Mexican front the differences are normally either huge or not as huge but there is a difference. Which one you choose really depends on how much you want to spend imho as there is no harm in getting a Mexican.
2005 Martin DX1R Dreadnought, 1994 Fender USA Lonestar Stratocaster, 2005 Gibson Firebird Studio, Aria Acoustic 4String Bass, 25W Fender Champion 110, 100W Peavey Linebacker Bass Amp, Crap Amp, Lots of Boss Pedals