For sound quality :

 

The first thing you have to do is to break it down into categories. Omnisphere is a perfect example, what do you mean by "in it's day", for the price, it still is given the samples and so on included. It's also still extraordinary, given the newest version, with what you can do as a sampler, it has loads of features for designing your own sounds most people never use.

It falls into the same category as Steinberg Halion, UVI Falcon, and, as of the version 2, Serum. The first thing is to break them down clearly into the intended purpose.

 

Another example, which aren't pirated much because of they're very good prices and frequent sales, are HoRNet plugins. If you're looking to do sound design and buy them, they're aren't necessarily going to blow you away, nor should they, they're for mastering. You have to know they're mastering plugins, not necessarily sound design plugins (though some are), you have to make sure you categorize them correctly. Make sure you check the page of the developer and know what the intended purpose is.