Well I looked at it from beginner == cheap and I inferred that from selection of guns the OP proposed. How long does a beginner gun need to last? The G&P should easily last a season.
My first gun was a G&G CQBR MAX, and I think that was an excellent starter gun. I still have it and it is still stock. At no time would I have wanted a plastic gun or would I suggest a plastic one.
But that is just me.. do whatever..