For those users with enough DSP to use an instance on every channel, the five Unison capable channel strip emulations (the lack of a Unison SSL channel looks like an omission to me - Yes please UAD?) namely the UA610, Neve 1073 and 88RS, Manley Voxbox and API Vision are very special plug-ins. In a similar way to the Studer and Oxide tape emulation plug ins, a lot of the point of these channel strips is to use them across a whole production and to let the cumulative effect bring a production together into a cohesive whole. It was the 88RS which finally convinced me that I needed more DSP but if I had got to the API Vision strip first I think would have reached the same conclusion.
Both the 88RS and the Vision are similarly well featured, based as they are on thoroughly modern consoles. They are both gorgeous. Russ did a very thorough review when the API was released and rather than duplicate its content I include it here.
Sweep Filters
Some of the things I particularly enjoy about the Vision channel strip are the excellent sweep filters. The high pass is 12dB/Oct and the low pass is 6dB/Oct - my preferred slopes.
Expander/Gate
The 235L expander/gate has some magic to it in that is just seems to do what you want without the meticulous setting up many plug in gates require. It is fast, though not as fast as the 88RS (100us and 50us respectively) but it is equally benign, somehow avoiding the faff which can so often accompany setting gates and expanders up.
Compressor
The 225L compressor's defaults seem quite aggressive (4:1, hard knee) but the default setting of Old (feedback) style make this a little more relaxed and switching to the more familiar feed forward detection illustrates this nicely.
EQ And Preamp Sections
The EQ is the star of the show, it is API after all, and the 550L's four bands of proportional EQ are as sweet and forgiving as you would expect. The 212L preamp section offers colour and can be overdriven nicely with the output allowing you to pull back hot signals back by 24dB.
Complex But Lovely
This is a complex channel strip and if I had a criticism it would be that it looks cluttered and is a little difficult to read but it sounds glorious. If your consoles taste owes more to LA than Lancashire then you'll really enjoy Vision.