The Phox has the added advantage of coming with a pump, hell buy it from Pellpax and the only thing they do not include is rabbits and pigeons!
The Phox is based on the Ultra, the trigger is a Gamo SAT, it works. I have one. Never got the pump, or the scope either, I had both so used them to get money off the package at the gun shop!
Had a Rotex, the first one was woefully underpowered, the second was ok, just did not feel right, the Phox does!