I would advise against the G&G.
They perform very well in their price range, and I was very happy with mine...
But the clear plastic lower receivers are a major liability. If you are an experienced paintballer you're probably going to play pretty hard, and the clear plastic lowers are unfortunately very brittle in key structural areas.
As for the style and accessories lumped into that gun, I can see why you'd go for it. It's got a pretty attractive body kit. However, as a former paintballer myself I can tell you that the headspace and movements typical to paintball have very little cross-over to airsoft. You'll have the advantage of being able to play without hesitation right off the hop, but you will have to unlearn some habits and learn some new ones to use an AS gun effectively.
My best recommendation would be to
1. Get AV'd as you said you would so you have a greater variety of sources to shop around with
2. If you want an M4, don't get one with a clear lower. If you must, expect it to fail and be prepared to drop coin on fixing it
3. Amongst affordable M4s, scuttlebutt says King Arms is one of the best deals around
4. Buy a basic model. You'll have enough to worry about when getting accustomed to AS guns that extra accessories and doodads will get in the way.
Stuff like fancy body kits, grips, alternate stocks, flip-up sights, optics, lights, PEQs; they're only going to help you out when you know what works for you and why.
-Appropriate clothing (BDUs, Helmet if desired)
-Load Bearing equipment
-Battery charger (a good one like the IMAX B6), extra battery**
-Basic tools (usually Allen keys, screw drivers, gearbox lube)
-Accessories (optics, grips, makeup, purse, etc)
**Ideally these are purchased in one go