I really think it depends on the brand of gun in which you use them. I've heard horror stories that have scared many away.
I've heard people say, "I'll never buy anything but factory mags," not knowing that Mec-Gar and Pro-Mag have been making factory mags for many guns for years -- under the gunmaker's brand name.
Pro-Mag seems to have been one of EAA OEM mag makers for a number of years -- so they make "factory" quality mags in at least some cases. I think they made them for CZ, too. (Mec-Gar is making all of CZ's new mags, however.)
I've had great success with Pro-Mags in CZs, Witnesses, a S&W 669, a Beretta 92, amd a S&W 5906.
Although they were a problem at first, I was able to make some very inexpensive mags for the P-210-6 work fine in that gun. (I had to reshape the follower, which was metal.)
Mag springs in Pro-Mags seems to die more quickly than other factory mags, and their plastic base plates (used only on some models) aren't very durable. They'll replace the base plates for you, without questions.
Quality control seems to be erratic -- with some mags working beautifully, and some not working at all. But I think this was more true of older mags than their newer production.
I wouldn't hesitate to buy more. And I've found that Pro-Mag is very good about making it "right," if you have a problem.