I would recommend getting something that has interchangeable magazines, i.e. M4, AK47. At least this way, if you run out of ammo in the middle of a firefight, you can ask for a mag and one will be given fairly easily.
I'm just a chairsofter right now, but I do have a SCAR-L with a foregrip and an ACOG scope, and I think I'm fairly well off. It's all up to personal preference.