Owned Diablo Wrath and SP ION.
Currently own a Promaster (backup)
Gloss Red FS-7 w/ Naughty Dog Body. Red CP shorty reg, Red CP trigger, Shocktech mini drop, Redz on/off, no-rise Q-lock feedneck. Red Halo B, PMI HPA 68/3000 (550psi) and Redz Pepper Sticks.
Out of the box its pretty good, but I would recommend a barrel kit and a new on/off.
O-rings (minor leaks)
Efficiency - 700 shots off a 68/3000
Overall I am extremely happy with my purchase. Although I have not owned another high end gun, I have seen many other high end guns in action. The reason I bought this gun was mainly because of the reviews and price. I could not find another marker of equal capability for the price.
Every other high gun of equal capabilities and equal reviews was priced 800$ and above (without ups, or required add-ons). Other guns I was looking at was the Proto Matrix and the Shocker. The Matrix was cool but I would have needed to buy an on/off, and new board for ramping to make it competative.
In game, the FS-7 is easy to move around with, light, and accurated. Its an easy marker to snapshoot with because of its size and weight.
I got my nd body FS-7 fs-7 for 650$ and it came stock with ramping, on/off (crappy), and twist-lock feedneck. Essentially, I did not have to pay extra do make a high end marker work.
It is easy to maintain and one-bolt field strippable. The bolt is easy to lube, but does require lubing after a day's use. Every now and then you get a niggling air leak, but can be remedied with a new o-ring or extra lubing. Setting your regs can be complicated if you are new to paintballing.
The FS-7 is very light, fast, well balanced, and very accurate.
In conclusion, I believe you should not have to pay extra to make a high end gun operable orcompetative. If you want a marker that is super competative and don't have to pay a lot, get it! Honestly, there is no other marker that performs like this gun for such a low price. Because of its cheap price (575$ for a stock matte colored marker) and high-performance traits I give it a 10.