I've purchased a very light (and dirt cheap) alcohol stove, and I want to use it on my backpacking trips this year. It fits perfectly inside my GSI cook pot, and that also saves on bulk. However, I hear that alcohol stoves don't do well at altitude. Is there any truth to that? If so, how high is too high? Granted, I live right at sea level, but my tests showed that 2 cups of water boil in about 6 minutes with this baby, so I figure I wont be underpowered at least.