I have extensively used nearly every high-end gun, and while many come close, I have to say that the Emag, coming stock with the anti-chop Level 10 bolt, and an incredibly consistent inline regulator, very low profile, and the 2nd lowest ball pressure (2nd only to Matrices) really stands out.
Emag w/ Level 10
Chrome Warp Feed Left Body
CP 2-Piece Kit
Warp Feed w/ 12V Mod and on/off switch
EvoII w/ Y-Board
Center Flag DynaFlow 68/4500
Custom Products Lightning Drop
If you got an E-mag used, and it doesn't have Level 10 (LX), then I would strongly recommend that. With LX, it is unbeatable, but without LX, you run the risk of a chop. Unless it's very finely tuned, that may happen more often than you'd like, and the unfortunate thing about Automags in general and E-Mags in specific is that, due to the bolt system, a chop will get paint shell and paint all over the bolt, spring, breech, and possibly the power tube. Needless to say, this will turn any idea of accuracy into crap, and you'll need to spend at least 1 FULL minute getting it all clean... You rarely have one full minute on the playing field.
Other than LX, you have the option of getting a ULE Body (cocker threads, and very light) and upgrading some cosmetic things, and you could get an X-valve (much lighter, and made of aluminum). However, I would only recommend LX. The rest are personal preference only.
Very consistent regulation (280 280 280 280)
High quality (AGD)
2 star warranty system
The weight - Easily solved by getting a ULE Body and an X-valve
I was extremely impressed with my E-mag. Like I said above, the very high-quality inline regulator ensures consistency. In addition to that, it is a very low-kick marker, and very low-profile, in addition to being extremely fast, and quick recharging (26cps without measureable shootdown). The latest software available for it allows up to 24bps in semi.
AGD has always made incredibly high-quality products, and with the warranty system of "Stars," it's very nice to be able to send in your mag for a free rebuilt (redeemable by one star). The E-mag has two stars.
Easily adjustable trigger, very light pull, and doesn't change with use. You do not have to constantly keep adjusting it, and fine tuning it.
Very low cyclic mass - Very low kick. I can put the E-mag's back right up against my mask and when I fire, I will barely feel the kick. I could put it to my bare forehead, or temple, or anything really, and not suffer any pain, nor feeling at all.
Very small profile - One tube gun means that it's very short (heightwise) and it also is very short from front to back.
With the addition of LX, this gun is unstoppable!
I would recommend this gun for any player who wants to spend the money. I would nearly demand that the tournament player use an E-mag, due to the extremely high qualties that it embodies.