Well if you had to pick which one between those four... I would pick the G&P. I myself have my eye on the G&P C8 Carbine. I am just waiting for my paycheck... I find the M4 variations the most versatile for additions such as tac lights, lasers, foregrips, M203's etc. Also this is an $800 rifle on sale, I myself would consider taking advantage of it. Hey, look at some reviews on youtube, even if they're american it doesn't matter, it's still in most cases the same rifle. Hope this helps coming from a fellow newbie.