If you do a search, you'll find numerous threads on AZ Drivelines, gloco, etc. He's got multiple names to diffuse some of the bad publicity, but it's Oscar behind all of them, and they all suck. If you get a good shaft, it's pure chance and luck, if you get a bad one or need any kind of service, he will absolutely and without doubt make it your fault. Even if you've got it in writing and there is no question he screwed up, he'll still claim you are wrong and he is right, and you'll get no support what-so-ever. I've seen some of the garbage he produces, including welds that don't even touch both pieces of metal. And I know several people who got charged for stuff he didn't provide even though it was itemized on the bill. This includes thicker walled tubing that turned out to be same as stock, new joints that clearly were not, new CV pivots and machining to replace when that was clearly not done, and clearancing on a CV yoke that still had all the casting marks with no signs of modification. In every case that I am aware of, when he was called on it, he flat denied any wrong doing and provided no corrective action. He is a POS of the highest order.
That said, I know of only 1 person who seems to do ok with his shafts. If you want an alternative opinion, talk to Rob (therobzilla) who seems to have done ok and been treated ok. <shrug>