I have not had mine long term but i have used it a good bit, enough to put it through its paces (The XFG)
It is without questions a brilliant GBB, gas efficiency is very good (always get the last shot off even in the cold) the 'kick' is potent, the hop is easily adjustable to suit your preferred flight path (it lifts .28s perfectly) its very well made, especially when comparing it against the likes of WE! The glow in the dark sights are a nice touch, as is the raised stippling on the grips, it actually works. Material wise, the lower frame is very well made, as is the outer barrel and slide, again leagues above the likes of WE etc....
In summary i paid very little for mine new, (£89) and i spent the same again if not more on spare mags, i have not regretted it one bit. For the money you will not get better out the box.
I have not yet found a decent locking holster (fobus etc) that it fits in so ive reverted to a viper adjustable type (so keep that in mind, depending on what sort of holster you wish to run)
I will happily recommend this GBB to anyone, it really is a great little thing.