New M4

[BringOnThunder]

Well I have decided my AA L85 needs retiring (already)
I am looking for a new M4 of some for (sorry this is going to sound very "WHAT AM BESTUST GUN?!?!?!")
Have been looking on a Popular Tennessee whiskey Airsoft shop.
I have tried to research this but I keep finding contradiction grr
the three contenders are
G&P M4A1 Carbine £220
Classic Army M15A4 Carbine £240
Classic Army M15A4 C.Q.B. £350

I was lead to think G&P is better than CA yet still a lower price? Could it be because it is an outdated version and the CA's are better?
also with the CQB is the extra £110 that is plonked on top just the RIS, Crane stock and forgrip? It looks like it to me, seems abit of alot of money just for that? as well I could buy a side arm instead!! although the larger Battery compartment would be usefull. Also I plan on running whichever I buy ootb until a part breaks then I will replace bits as and when. Sorry for the essay
Thanks
Matt