If you decided to invest into the UAD plugin field, and you find yourself wanting to add some SSL warmth or API grit to every channel for that "authentic" analog desk sound... well then you'll need one of these. And yes, the performance is linear, so if you for instance have Apollo Duo of somekind, the performance of the Octo is pretty much exactly 4 times of a Duo. However, keep in mind, that the workload distribution over multiple USB devices isn't always as logical as you think. Also, you don't actually need a UAD interface like the Twin or Solo to use a Apollo Satellite, you can actually just buy a Satellite as a DSP-accelerator only, i.e. you can keep your existing soundcard and just use the Satellite to run your UAD plugins on. But then of course, you can't use the fantastic zero-latency Pre-Amp magic that the Apollo line-in interfaces has. Just saying. So in short, does the job, don't buy a Quad satellite, get an Octo right away, it's way better price performance.