I have three pairs of skis with the VIST system - Hart Phoenix, Hart Pulse and VIST RC Team.
I have nothing but highest praise for the system. In terms of convenience, you need only one pair of bindings for as many pair of skis as you have with the plates on them. Advantage for traveling - obvious.
Performance wise, the ability to move the binding back and forth in small increments (3-4mm?) allows the skier to fine tune center of mass. This is particularly important when the manufacturer's mounting line is not the best mounting point. There is also a performance advantage having the boot on a plate. I do not know what the physics are. But I do know that many ski race models come with VIST or Marker plates. And if I am not mistaken, the ski racing world limits the height of plates. All I know is that I feel more power under foot when I lay over my Phoenix's (66mm waist). The extra height may also help avoid booting out with high angle carving.
Like others, I suggest you contact Tom at Norse House. He is a good guy and can steer you to the right plate. That is important. I have the SpeedLock Pro on the VIST Teams which are the very same ski as the Hart Phoenix which have the TT plate (both made by Blossom in Italy). The VIST's definitely feel stiffer with the Pro plate. I suspect Tom would recommend the TT plate and I would agree. The other cool thing about the TT plate is the is 4mm custom fitted shim that can go under the toe piece to reduce the ramp angle of the binding. If you are not familiar with that concept, the bindings are not flat - the heel is higher by appx 7mm. Some folks, like me, prefer a more upright stance (easier on these old quads). So the shim under the toe reduces that angle. There is also a really cool boot scraper that attaches to the plate (got to get that).
There is a lot in the 'Ski Chic" VIST line that is fluff to my eye (ie: the clothes). But the plates and bindings are the real deal.
Hope this helps.