If you want to try to stick with OSX you could try homebrew[1] + homebrew-cask[2] as a package manager, even if it probably won't be as good as what you were used to.

For battery life if you want to switch to ubuntu, the issue is probably that you are not using a good power manager which OSX does automatically behind the curtain. This could be a starting point : http://askubuntu.com/questions/285434/is-there-a-power-savin...

[1] http://brew.sh/ [2] https://github.com/caskroom/homebrew-cask