I've probably flown about 10 to 15 cycles on each now, and can say without a doubt that these are good performing packs. I'm getting explosive performance from them on my 5" and 4" quad, especially compared with 4S. Not only do they perform well, but they've proven to be durable as well. I'm not a great pilot by any stretch, and have no problem admitting to some recent crashes. As a result I had a replace a set of props on each quad, and even a broken arm on one. These 6S packs however held up great, even on the 4" where they were mounted underneath.