I have used a Pro QD i3 for the last two and a half years. I was happy with it during this time. The i3 mechanism is very simple - I even opened it when it leaked a small bubble stream near the lever (it proved to be some sand that was causing it, I cleaned and lubricated the lever and it was fine for the next 1.5 years). The pockets are large, but stay clean when not containing anything. It deflated and inflated easily through the lever. The body fit was solid. Overall, for a jacket BC, I would say it was very good.
On the down side - I saw somebody breaking the shoulder buckle after two dives - which caused a 3 weeks return to the factory.
I have switched this year to a DSS BP/W, following the word of scubaboarders, and I am very happy. I would not return to jackets, but if you want a jacket, the Pro QD (with or without i3) is a very good one.