Let me start by saying that this gun, with some minor upgrades, is absolutely amazing. It's been through many games and has very rarely given me any difficulty.
Now, I say with minor upgrades because, like any gun that doesn't cost $250, this isn't perfect. The gearbox is good, the hop up is good, the plastic body, although plastic, is very strong and has seen some rough play (I've had this gun for several months now). Out of the box it pulled right around 350, after some breaking in around 340. For the price, not bad at all. The ROF is very good on this gun, and although I don't know the exact BBPM, I can tell you that it is absolutely fine with an 8.4V. The barrel is a bit wobbly out of the box, but a little tightening of the hex screws fixes that (NOTE: almost all M16's of this style experience some barrel wobble, and no worries, it isn't that bad). The high capacity mags it comes with work very well (although i bought some metal MAG magazines, i prefer midcaps).
Now, as, for upgrades you should perform on this gun, the first two that come to mind are a one-piece barrel and a tightbore. I suggest Madbull for both (the Madbull M16 Length Barrel and the Madbull Ver. 2 Precision Inner Barrel). I have both of these upgrades and they perform extremely well, increasing accuracy, fixing barrel wobble, and drasticly reducing the weight of the stock steel barrel (this balances out the gun very well). I would also suggest replacing the hop up bucking along with the inner barrel, as the bucking can become damaged removal/installation. If you have the money, rails and a metal body are good upgrades.
Overall, considering the price, I believe it performs very well. I've seen my friends rifles, and with the relatively inexpensive upgrades I've performed, this M16 greatly outperforms many other AEGs. ECHO 1 has really stepped up their game, and this is a fine example of their dedication to great quality for a lower price.
Now, to the pros and cons:
Price (considering the quality you get)
Plastic (Pro or con. it's strong plastic, and it's light, but some prefer metal)
Weight (it's a beast of a weapon, if that's your style. as stated earlier, upgrades can reduce weight)
Great ROF (considering stock battery/parts, it's very good)
FPS (Not too low, not too high)
ECHO 1 Customer service (they are extremely helpful)
Rails under carrying handle (I use a leapers 40mm red dot on mine)
Full stock (fits large battery snugly)
Easy to maintain/disassemble
Plastic (again, pro or con, the handguards have a tendency to break easily if dropped)
Weight (depends on preference)
Length (not great for CQB, but come on, it's an M16)
Barrel wobble (easily fixed with one-piece barrel or by tightening hex screws under barrel)
No rails (although a dmr version is available and a rail systems are easy to find)
None other than that! This gun is amazing quality for the price!
Rating: [5 of 5 Stars!]