G3 IQ, G3, Ion, Shocker NXT. Hands down I loved my Shockers performance but it always had vision issues, the ions were nice but a little harder to maintain and compared to previous G3's the biggest change was the trigger.
I use the G3 Specr equipped with a deadlywind fibur barrel fed by a rotor loader and powered by a crossfire 68/4500
Overall compact size and lightness
My favorite things about the specr and all G3's is the ease of serviceability, it is awesome to be able to pull the rear cap off and clean all the way through lube and be done in a matter of minutes.
The new manual with the Spec r is way better than the old poster manual they came with. It is much more in detail and more user friendly.
The new trigger as stated above is a lot nicer than the old trigger and is magnetic and adjustable.
The milling has changed since the last generation but this is mostly cosmetic although it did lighten the gun a little.
I love the G3 Spec-Ras my main gun. At the end of the day after playing I don't feel like I have been toting around a big heavy brick with a barrel. In the price range it is very hard to beat and comes standard with clamping feedneck and a lever asa that is awesome. I'd say if you are looking for a marker in this price range try it you'll fall in love.