G&G GR15 or CM16 AEG

[C4lv1n]

I was looking at buying my first gun, and I like the M4 style. I've been looking at these two for a while now but I don't know if the blowback is worth the extra £60? I think the GR15 also comes with metal RIS rails?

I was wondering if anyone could give me any advice on if the extra money is worth it or not?

Cheers

[C4lv1n]

Re: G&G GR15 or CM16 AEG

Is this a good buy or am I looking at the wrong thing? I'm looking to spend around £200