I've found a forum of sheet metal workers, the guys who make car panels and hoods and the like from scratch...
LOTS of them still use OAW for body work on aluminum of all things. Most seem to swear by OAW and at the gas shielded arc processes.
The claim is that OAW welds are stronger, but something tells me its strength is that OAW anneals the sheet in a wide area compared to GTAW. Which is great when they procede to smash the weld and surrounding area flat with a hammer.
Sorry, not about pipe...