Difference between JS and Stillwell VSTs

There are a number of JS plugins in Reaper that have the same name as the Stillwell VSTs. I know they are from the same developer, and that the VSTs have a better GUI, but is there a difference under the hood?

Anyone?

Actual metering ( a major feature in itself in the compressors), better performance (very significant in some cases), better looks… plus the ability to use look ahead processing in some plugs which opens the door for all sorts of neat stuff (EventHorizon in JS doesn’t do this, in VST it looks ahead 2000 some samples for example). Also over sampling is included in many of the plugs which makes the plugs better sounding in general. Plus there are some added goodies in some plugs. (EventHorizon again, in VST it has a limiting AND clipping mode. JS only has limiting.)

Needless to say, most of Schwa’s stuff can’t even be done in JS due to the limitations of the language. I am a huge fan of his dithers. To the performance point above, the compiled VST uses almost 90% less CPU than the JS version.

Thank you for your reply. It is extremely helpful.