Manufacturers each have their own quality programs, quality sampling rate (frequency) and tolerances and I haven't seen them published. For many cuts some tolerances (such as highly precise diameter) doesn't matter for most cuts but there are certain types (i.e. dovetails, at least when using the Incra jig) where its very important. Some of the high-end bit manufacturers (such as Whiteside) have earned a very good reputation for consistently delivering quality products, albeit at a premium price. Every manufacturer can have an occasional out-of-spec get through too, so there's no guarantee but if precise tolerance were important, *I'd* choose Whiteside.
This doesn't mean you can't find a very precise bit in the proverbial "bargain bin", but I wouldn't count on it. As you move up the ladder, this is one of the things you should expect.
I'm also with Cassandra on this... Freud also makes good bits. It's a bit of a "Ford vs. Chevy".. or more like Bosch vs. Makita... opinions are usually stronger than the true differences.
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