The best batteries I have ran, are the Vant 4600 90C batteries offered at DirtCheapRC.com 44.99 ROAR legal, and the best warranty for a battery company. We have 2 of the older 75C batteries that have roughly 200 cycles per battery, and they are just now getting soft, but no swelling or puffing of any nature. MANY LVC cutoffs with them in this time frame as well.
I have an SMC 4600 70c shorty, and while it offers great punch, and low IR, it has swolen. I talked to Danny from SMC, and he said all of his packs do so. While I appreciate his honesty, I cannot run them because I race a lot of roar events, and they would fail inspection because they are swolen. I also have a 65C Reedy shorty pack that is also a great battery no complaints, just dollar for dollar I can get 2 vants that are better performing batteries for the price of this 1 reedy.