People are looking at this from the wrong perspective.
Torque is what an engine "generates", the power figure is the result of a mathematical calculation based on the dynos measurement of that torque. The dyno doesn't measure power it measures torque and calculates power by multiplying the torque figure by rpm. Therefore there is no question about the authenticity of the torque figures and if anything it's the power figures that should be in question.
Furthermore peak torque and peak power seldom if ever happen at the same rpm and if you look at the graphs, you'll see that by peak rpm the torque figures for both systems is almost identical which is why the peak power figures are likewise.
Like Denny pointed out (and what most people are ignorant of) is the fact that "TIME" plays a huge part in how a nitrous system performs.
Here's an analogy for you;
Take 2 cars (no nitrous, just basic road cars), both have the same peak power but one is tuned to perfection across the whole rpm range whilst the other has a huge flat spot due to being badly tuned. Put them both on a dyno and they both make the same peak power numbers but the torque and power "CURVES" would be totally different (except at peak power). Now take the cars on the road and would you expect them both to accelerate at the same rate - certainly not, the well tuned car would leave the badly tuned car in it's dust.
It's the same with nitrous systems, ours is "designed" to perform efficiently and is "well tuned" - the rest are just bits thrown together by people who have no idea that you can even tune a nitrous system never mind know how to actually do it!!!
If anyone doubts this fact, just take a "good" look at a Pulsoid and compare it to all other solenoids. Even a blind man could appreciate that the nitrous has an easier path through the Pulsoid than it does through any other solenoid. Therefore EVERYONE who uses conventional solenoids in their kits either does not appreciate the importance of this fact or they are happy selling their customers inferior and inadequate components. Either way I wouldn't be buying products from them!!!
Here's another point to keep in mind, the more efficient the system works the less nitrous you use to achieve a given performance result. Therefore whilst you "might" save a few £££s on the purchase price of any other kit, the extra cost of nitrous wasted through inefficiency will soon eat up that saving, so not only would you have bought an inferior system that wouldn't make your car perform as quick as ours but you'd also be paying more to run it!!!