Things I liked: Bought this for my wife who could not break the barrel of the Benjamin Trail NP. She loves it. Had previously purchased a GAMO Extreme CO2 - what a waste and disappointment - broke twice in less than 10 shots - first time warranty repair - second time, chucked it as appeared to be the same issue - dry firing with no CO2. With the 850 - at 25 yards and the scope from the GAMO - she consistently puts 8 shots in a 1-1/2" diameter ring as is - out of the box less than 100 shots.
Things I would have changed: Less expensive attachment to use smaller CO2 cartridges. More positive feel for the clip to rotate when cocking to line up the pellet for the next shot
What others should know: With our ears, seems to be the same sound volume as the Benjamin Trail NP when shooting in our backyard. No neighbors have complained, yet.