There are a number of ways to make a sprocket, but for our purposes we can distinguish two: the right way and the wrong way. The right way is to machine from solid metal, either in one piece (old style) or two (new style). The wrong way is to press-form or lasercut from sheet metal.
Lasercutting was pioneered by a company called Cyclo in the 80s. Although Cyclo had a long and honourable history as a maker of aftermarket components, those sprockets were a bad move. They look the part, but are fatally soft. This means not only rapid wear but also the risk of deformation, and a deformed thread can act on your hub threading like a canopener on a can. One Cyclo user known to me lost his sprocket on a wet day while negotiating a steep downhill at speed in heavy traffic. Think about it.
I've chosen to pillory Cyclo because the company is long-since bankrupt and can't sue me, but similar sprockets are still being sold by a number of retailers who really ought to know better. Although they aren't usually branded, you can spot them pretty easily: the metal looks dull, and the edges of the teeth show a kind of seam. If you are offered one, you are dealing with a shop that doesn't have your best interests at heart. Take your custom elsewhere.