I'll elaborate more:
Having a realistic feeling gun is great, but in terms of actual performance on the field, the body being polymer or metal doesn't make any difference.
Thing is, we are mostly lumping around our guns all day and slowly drain our energy.
The weight of the thing will determine at what point in time you'll start to hate your life
I'd rather have an all polymer gun that is light and manoeuvrable than something realistic looking but that will tire out my arms quickly.
with that being said, Specna (along with Evolution, Dboys and Saigo Defense) offers more than G&G despite having a lower price point:
proper steel bushings, decent brass barrel, QC gearbox and rotary hop unit, whereas G&G insists on brass bushings, pressed tinfoil barrels and those stupid geared hop units that a) are more expensive to make and b) they are flawed in design because they tend to unwind themselves. And they out screws on the wrong side of the gearbox -.-
you pay for the brand (and a fancy polymer body with the 2.0 series) but get outdated internals.
I know you can replace those parts on a G&G buy why pay more and replace parts when you can spend less and have them on board already?