You'll want more than one gun...anything else is a lie.
WHEN you decide to get another gun...keep mag/battery interchangebility in mind. It just makes things easier and more cost effective.
The best way to improve the accuracy of an AEG is to take 10 big steps forward...if you need more accuracy take another 10 steps.
Use good quality 0.25-0.30g BBs for consistent/"predictable" shots.
Pick a rifle that "fits" you best...carrying/aiming/shouldering/shooting/etc...
If you've got "short" arms a rifle with an adjustable/collapsible stock will feel better. If you're short...a full size M16 might be a bit clumsy as you bumble through the bush.
The G36C has quite a short barrel and the mags are a pain in the a** (in my opinion) getting them in/out of pouches. Most gear is for M4 sized mags...but dedicated G36 rigs or rigs with triple/quad M series pouches will work. They're just HUGE.
The M4 series are like the Honda Civic of the AEG world...there's just about 30 variations of every part of it to tweak/tune/customize.
Good luck, have fun