I currently own and have used Crossfire HP/LP tanks, PMI tanks, Empire Fuel tanks, Dye Throttle tanks and a Luxfer tank with a Myth Reg. Based on my experiences, only the Crossfire tanks have performance as good as the Ninja tanks, and the Ninja tank has an adjustable output regulator giving me flexibility to change the output pressure on the bottle.
I shoot a 2K5'd GZ, Excalibur, FL Viking, and have 12 other Intimidators...primarily shooting a Vice. I run a Rotor or Pulse loader with a PMI Pure Energy or Crossfire Tank.
Tank weight, size, flexibilty to adjust the output pressure.
None at this point.
I received this Ninja tank in a raffle at the USPL DC Challenge event in August 2009. I've now used it for several weekends of play on my Vices and have been thoroughly impressed with the quality of the tank and the flexibility it provides. I primarily use Crossfire tanks/regulators as I've found them to be the most consistent in terms of output into the regulators. The Ninja has performed to that same high level. The advantage of the tank is that the owner can change the output pressure on the bottle by altering the configuration of the shim stack in the bonnet/regulator on the tank.
Removal of the bonnet, while the bottle is empty, is easy and requires little effort. By adding or removing washers you can fine tune the output of the bottle providing flexibility for people using LP only markers (Angels) or HP only markers (Mags, Sear Tripped Blowbacks) or mid range output for Ego's, Intimidators, etc.
The consistency of the output and flow has been very good and ranks up with the Crossfire regulators (which I believe to be the proven winner over a sustained period of years). The ninja tanks are at a lower cost point in the industry than many other bottles and the individual regulators are only $30ish, easily affordable for cost conscious buyers and ballers on a budget.
All in all, a very impressive tank. I would recommend them!
A very solid tank with lots of potential for a variety of players!