The Pi hardware isn't the best, nor is it cheapest, but the community has a lot of support built around it. There are pre-built images for all sorts of tasks and people have gone and done a lot of the hard work on it. I have a Pi and a BeagleBone and the BeagleBone, although slightly faster, has some braindamage that is hard to ignore. It has a built-in version of Linux, but it's hard to update and the eMMC space is a little too small to be really useful. So you boot off of SD instead, but that requires you to hold down a button while it is booting to bypass the eMMC. But then you notice that it doesn't have as many packages available as the Pi. No Chromium for instance, so you're stuck with the really stripped down and mostly broken browsers. The worst part is that by industry standards, the Beaglebone is above average. You can pick up one of the many much more powerful and featureful AllWinner boards, but find yourself utterly stymied by the horrendous state of the documentation and lack of community. It's really hard to get real work done if you have to do all of the groundwork yourself.