There's another thing to consider. M16 and variants (M4's, etc) have V.2 mechboxes. G36's and AK's use V3 mechboxes. A v3 mechbox is stronger and generally more reliable than a V2 mechbox and slightly easier to work on.
The G36 series also comes apart really easily. You can do a barrel swap in a G36 in < 5 minutes. New hop-up? < 5 minutes. Take the entire mechbox out? < 5 minutes.
For a "first gun" I highly recommend a G36. For your budget I'd try and find a Classic Army one. Internal they're pretty good, but externally their bodies are excellent -probably second only to STAR/Ares for quality.
Originally Posted by Freeze
Warning if you get a G36...the fuse will pop out easily (if there is one) and don't use LiPo....my wires burnt and melted, yes, melted, after only about 6 or 7 uses of shooting targets at home....
However, I'm willing to bet that mine was a lemon since I don't think many other people managed to do what I did....
My CA36 has been going strong for years. If your wires melted you were using a battery that was WAY too powerful, a spring that was way too powerful, or had some binding issues going on and didn't fix it. Did you upgrade the wiring before upgrading the spring to 430? If not, that was probably your problem.