It's commercial realoaded to SAAMI specs. So not much of a difference really. Contrary to the .38special, which come in bulk packs of 50, the 9mm come in boxes with trays, just like PMC or american eagle.
The only downside to the WM is this: A few rounds per box have aluminium casings. This means if you reaload yourself, there's gonna be a couple of cases per box that you should discard and not reload. I'd say about 5 rounds per box of 50, give or take.
Bottom line is: Just try it people. It's commercial reloads, WM need a commercial licence to do it, they test a sample and all. It goes roughly through the same process as new production, except for the production of casings. It's not like some doofus with a Lee press is making bullets in his basement between shots of gin. If it doesn't perform to your liking them keep the rest for plinking or practice, or sell it for a very minor loss to the guy next to you at the shooting range, and buy something else next time. But it'll neither blow up in your face nor bankrupt you (well, not anymore than new production would anyway).