Plastic for plastic, CYMA is better than JG but for price, but you can have a steel Dboys for $20 more. Dboys are the most bang for the buck at around $120.
Internals are all in the same ballpark for the lower end guns.
Full metal: Echo 1's are (slightly) upgraded CYMA's with a warranty.
If you have the cash though I recommend a CM048 at $180. Solid metal body, real wood, VFC knock off. It shoots a little hot out of the box but will calm down after 1000 shots or so to 420fps with .20's and 375ish with .25's.
I own the Echo 1 version of the RPK. The gun is virtually the same but in the RPK variant and even hotter. The receiver under the stock is even marked CM048, and shot 375fps with .28's out of the box. Right at limits for LMG's.
CYMA/JG plastic body for $100+
CYMA/Dboys metal body for $120+
CYMA high quality for $180
E1 Red Star (CYMA+) $200-250
