I had me an SLG and it was broke before i even got to use it for the 1st time. Was leaking Air near the ASA
but in the end i spent more time out fixing it than in using it, but saying that, a mate of mine has one aswell and his has never failed. So its the luck of the draw. In the End a gun is a gun.
All the Planet Eclipse markers are famous for there reliability. Your best bet, is to get yourself down to your local, talk to as many people as you can, get as much information as possible and ask nicely to see if you can borrow there markers for a try out, before you spend your hard earned cash. Most importantly protect your face and get a good Mask.
Iv had Dye I3 and I4s, love my I4, if you have a small head/face there perfect.
Not to mention do some research.
http://www.pbnation.com
Thats a good place to have a look at reviews
Enjoy