Yeah, i got an E99 and there's nothing i can say that's bad about it. It rocks.
So far i've shot a case and a half of paint through it with no breaks.
You can set the trigger pull mouse-click short, and then its a case of how fast you can move your finger. You can take the bolt, spring, striker, and velocity adjuster out with the removal of one pin, really handy for cleaning/servicing. You can take it down to all its component pieces in under 5 minutes, very easily.
When it's put together it feels nice and solid...no play in any parts appart from a slight sideways slop in the trigger (easily fixed with a strip of feeler gauge or a very thin washer if it bothers you that much).
All the electronics and battery are accessable via the removal of the left grip panel, though, after sticking the battery in i have never needed to open the panel since.
The 12" stock barrel is pretty accurate too, although i think would the first part to be upgraded though.
The marker has given me no problems at all...i highly recommend it..especially for the price. I don't think theres anything you can compare it to at that price.
It is vastly upgradable, not that it really needs it, and i think it should last me quite some time. Go get one!
Hope this helps!