Unison is a feature of UAD plug ins which really sets them apart from their native counterparts. Near zero latency can be achieved in other ways, though the guaranteed performance of UAD plug ins is very seductive, especially at the price point of UAD solutions which, while at the premium end of the plug ins market are still much cheaper than accessing AAX DSP plug ins.
Tracking Through Unison
Unison plug ins offer added value at the tracking stage because they change the way the plug ins "feel" to use. When I read about the introduction of Unison I was full of admiration for the execution of the strategy as all owners of Apollo hardware already had Unison equipped preamps, the hardware had been quietly implemented for some time, a ready, fully equipped user base was already in place. I thought this was a marketing masterstroke.
Mic Preamps And Instrument Inputs
My first experience of a Unison enabled plug in was the Raw Distortion pedal - The Unison features can be accessed through the mic preamps or the instrument input. The experience of using Unison enabled plug ins is hard to describe without sounding very subjective but guitar plug ins feel responsive and "alive" in a very noticeable way. I won't try to describe it further - if you have an Apollo you'll have experienced it, if you don't then find your nearest friend with an Apollo and try it for yourself.