It seems the Impact is, as of now, the holy grail of pcp design, accurate, high shot count, fairly compact, fast and smooth to cock. I see the appeal of semi auto, but to me personally, it is self defeating on an air gun, since most airguns have small magazines, limited shots and the process of refilling an air tank is much longer than center fire reloads. That said, due to the lack of any real recoil on pcps, semi auto is dandy for accurate rapid shots.
Semi auto seems to fall in the same category as 1000+ fps air guns and shrouded barrels (in the smaller calibers) they will build them because the buyers are there, because people will see "shrouded barrel" or "1200 fps" and think they need that. I fell into that line of thought when buying my first pcp. But after owning my marauder pistol, its just about as quiet with its shroud off as on, and as many veteran airgunners have proven, high fps tends to bring about poorer accuracy (in the smaller calibers).
For the complexity that semi auto adds to an air gun doesn't seem worth the payoff. I don't doubt they are fun to shoot though!
