The best advice I can Give you is to first decide what kind of gun you want... G36, M4, M16, AK, MP5, Sig..... IMO AEG's are better for the beginner. We can't tell you what gun is the best for you only you can decide that. Find a gun that fits your body, feels comfortable to you, suits your style of play and that you like. Keep in mind things like where the battery is going to go, is it going to be a tiny battery are you going to need a few to get you through a day of gaming. Mag availability and can you get pouches for those mags. Do you want to put an optic on it, can you put an optic on it. Do you want to be a rifleman, a DMR, a support gunner, a CQB specialist. If you're not sure of the role you want to play I would recommend a rifleman, this is the most versatile role you can play. Rifleman will generally carry full length or carbine length assault rifles.
Once you decide on the type of gun you want then do some research on the different brands that make that particular model of gun. Try to stay away from brands with proprietary parts such as pneumatic blowback units and unique hop-ups etc. IMO AEG's with blowback are very unsatisfying and only serve to make unnecessary noise and have extra moving parts that can break. If you want blowback get gas. If you do get a gun with proprietary parts make sure replacements are easy to get (KWA). Look for something with "Marui compatible" or "Marui spec" parts, these are non-proprietary parts they are the common standard and are readily available.
Edit** The AR (M4 M16) is the most common platform out there. If this thread goes the way I think it's going to go you'll probably want an M4 in which case everyone will tell you to get a King Arms M4A1, great value for the money. I would say that everyone and their grandmother has an M4... you don't want to use a gun for grandmothers do you?... all the "cool kids" are being different and rocking AK's. Get yourself a Real Sword Type 56-2.
Last edited by Kozzie; April 2nd, 2012 at 00:59..