What is the general reliability of aftermarket turbochargers?

[soupmagnet]

So, my factory turbocharger went out at 112,000mi, and luckily I have an extended warranty that will cover it, but unfortunately they will only cover aftermarket parts. I have the choice of either going with the aftermarket selection, or get the official Hyundai part and pay the difference (around $400). My question is how reliable are aftermarket turbochargers? And would it mater considering the high milage of the vehicle. It should be noted that the mechanic says he will not guarantee his own work if an aftermarket part is used, based on his own experience with aftermarket parts in general (also I am told that this is a pretty common policy among mechanics). Thanks!