I have been flying a 2 meter glider with a cobalt 400,direct drive with 8x4 prop, and the little motor puts out great power for its weight- running around 20-25 amps on 8 KAN cells; 1050mah NIMH. It puts out about as much as my AstroFlite cobalt 05 geared on 8 cells, and the Astro motor weighs 8 ounces to the Super 400's 3.5! I don't see how any motor, brushless or whatever, can do any better on 25 amps, 8 cells, because the wattage (around 200 watts) is about the same, and this is power! The brushlessmotors, and the Astro, are more efficient, so would run a little longer per charge, and they will no doubt last longer, but for the money, the cobalt 400 does great.
now the downside: I read discussions where people said the cobclt 400's came apart after a short time, and that the first models,with gold color, were bad. The next models, blue, which I have, some were good, some not. Then they brought out yellow models (hard to tell from the gold) which seemed O.K. After reading this, I broke-in mine exactly according to directions, which called for a lengthy break-in starting with small props and low voltage. At first my motor ran erratic as the brushes seated, finally ran smooth. Bottom line- for the huge difference in cost vs. a brushless with expensive controller, the Super cobalt if carefully broken-in, is a good choice for most kinds of flying. Now Hobby People has larger cobalt motors- 05's etc. that cost half of an equivalent brushless setup, and they have planetary gearboxes for them, including the cobalt 400. . I would try one, except that I have the Astro 05.