I love this thing. I just bought it and it performed wonderfully on the field. The rate of fire is phenominal, advancing upto 19 rounds per second. Dang. The trigger pull can be shortened to the point where the slightest movement sends a ball flying at your target. The field strip is great in the case of a ball break. The bolt can be removed in under 5 seconds, minimizing the time you aren't shooting. The foregrip is nice to have, because it isn't the best balanced gun on the market. The switch on the side of the grip is great, it makes the gun super easy to turn on. Easy change battery door is awesome. Don't buy into all that crap about it being hard to get to. it is really simple. i changed my battery in the middle of a game in a few seconds. the removable vertical feed is cool too, it makes cleaning the breach very easy.
First and foremost, the screw alignment on the regulator makes a drop forward literally impossible at this point. that sucks. screwing in my compressed air system is a little hard to do, but maybe that is my tank screws. the blow back is way too much, but just make sure you have at least half your hopper full, and it's fine. it does have the power to blow another ball out of the breach(i know from experience). the lack of an available upgrade to a 2 finger trigger might piss some people off, but you will get used to it. single isn't so bad.
I hear a lot of people whining about it costing way too mcuh at the price of $600. let me tell you something. if you bought the EM1 for $600, you got ripped off. one of the cool things about this marker is that there is no real need to upgrade anything on it, except maybe a better barrel. the OTP one they give you SUCKS. it doesn't even have an inner coating, just the aluminum like the outside. i would definately recommend this to somebody else. everybody seems to compare the EM1 to the impulse or the bushmaster, but i wouldn't know, i have never shot either of those guns. i would definately tell you to buy this marker if you have the means.