I've always had good luck with Safelite (highly dependent on the tech that arrives though), and I have had bad glass. I had an OEM windshield replaced for a vehicle with some aftermarket brand, and it had a horizontal "warp" in it that was right at eye level, so I had Safelite come back out to replace it. With no issues, they came back out with two pieces, OEM and the brand, and we looked at both pieces. The aftermarket had the same warp going across it, and the tech explained that it was probably from a bad lot, so we went with the OEM glass.

The only differences (beside the lack of warp) was the printing on the glass and the surround rubber, which was thinner on the OEM piece.