So I am new to the whole gun thing and am looking to buy either a M4 or an AR-15 and I am wondering if I should go with the direct gas injected or the gas-piston? I've been reading a little on both but I'm still a little lost. I've found some Bushmaster's for around 1K but those are the gas ones, however, I was looking at the Bushmaster BCWA3F16M4-GP (gas piston) and it is about 1500. Is the gas piston worth the extra 500? I guess I should also note that I am not really planning on shooting thousands of rounds through the weapon as I am in college and on a budget. Any help would be great !