Sorry to hear about the dealer treatment, but it's not only "buy Bosch", but *where* you buy them.
1. DON'T EVER BUY a critical part from flea-bay. Period. Lenses, bric-a-brac, accessories, fine, if they don't work you can throw them away, but don't buy anything that affects vehicle performance or safety, no matter what the alleged brand name is.
2. DON'T BUY FROM QUESTIONABLE SOURCES. Even good sellers get fooled and ripped off by marketers of good fakes and replicas, but at least they'll stand behind what they sell and take care of you. The others? Good luck, you'll probably need it.
3. The old adage still proves true: IF IT SOUNDS TOO GOOD TO BE TRUE, IT PROBABLY IS.
Dealers are well known for marking things up. But if they do their job, they're not just swapping the MAF for $1,300. They'll plug in the Star Diagnostic system and check and reset certain things (like trouble codes), diagnose the issue, replace the part and then reset adaptations (so you don't have to drive it carefully for a few days while the ECU relearns things on it's own), and they may also ready it for an emissions test.
All of that is valuable, but hardly THAT valuable, at least in my opinion. (And let's not forget that "free" car wash.
But it's not as though the dealer plugs in an OBD-II meter, pulls MAF codes, sticks in the new MAF and waves good-bye after 20 minutes and gives you that bill.
Take care and enjoy the ride,