I use a an eclipse shocker and never had any bother in eighteen months, very reliable, prefer it to my cocker. great rate of fire and pretty easy to strip and clean. Superb at the back with an 18" and perfect up front with a little 10".
However, the shocker is damn big and very heavy, so unless your my size it's difficult to use up front.
Also, very gas hungry, so for back, you really need a 1.9 tank.
On the plus side, it came in handy at storming the castle----- I used to knock the tent pegs in on the diablo cross.
So, basically, it's a sweet marker great ROF, accuracy and reliability (if looked after). But it's very gas hungry and a little large for the average person.
You either love 'em or you hate 'em.