The main difference between UAD and all others is the way they take the ‘processing’ away from your CPU. Their plugins are (not always but often) on another level. This means more DSP (or CPU usage). By sending that through their separate ‘processing’, it means you can still run your daw and other plugins.
Sadly, the starter is with the hardware, but it does open up a whole new world.
also its the relationship between the DSP Hardware and the plugins that is the UAD sound. plugins without the hardware wouldnt do it anyhow, thats why UAD is the king of the hill.
Here is the UAD usage chart where you can view by each individual plug-in; I had the same questions in the past, I think that investing in a UAD QUAD or higher worth the money and make the workflow easier. You can prob. find a cheaper unit on used/b-stock etc.
Yep be very aware these points about UAD - their hardware with the chips isn’t cheap and subsequently you could be finding yourself budgeting their use unless you’ve a load of them.
However many prefer offloading that processing to chips designed for fast audio processing like the SHARCS used saving their CPU for other tasks/native plugs - plus you can track with them…
The deal of $399 for 3+1 plugs is probably the best they’ve ever done as you could get 4 usually $299 plugs with it.