MagTech is made in Brazil.
My experience with it has been quite good, and when I see others writing about it, its generally with high praise.
I rank S&B, Denel, PNP, MagTech, IMI, and CCI/Blazer as shoot-alikes: interchangeable in terms of reliability and performance. If you can find any of them at reliable prices, buy it.
(Note: if I could find it at a reasonable price, I'd shoot ONLY IMI. [Israel Military Industries.] I think its the best 9mm fmj ammo you can buy commercially. You'll find it on sale from time to time, but its generally 10%-20% more than the rest.)
I don't like Winchester White Box, as I find it less accurate than the others; some also have reliability problems with it -- as it doesn't always extract well in some guns. Others swear by it. Avoid UMC. (Its safe and generally reliable, but quality control is spotty, and performance varies greatly.)