Only lipo I've had fail on me was a $130 Reedy stick pack. The bullet connector got so hot on the inside that it melted the casing and the solder. (I use proper "solid" bullets, not the birdcage kind, and I have another Reedy run in the same truck just as hard and just as often, and it is still good.)

All my cheapo Dynamite, Turnigy, Eurgle, and Haiyin packs are all still doing fine (though most only have 20 runs on them....the Dynamites have about 60)