OpenELEC is a massively cut-down Linux operating system designed purely to run Kodi and nothing else, so as Dave says, all resources (processor, memory, network bandwidth) of the Droidbox are channeled into Kodi instead of being allocated to various other apps as they are in Android.
I've found buffering is almost non-existent in OpenELEC and generally it's faster to respond, but it's not as well-supported as Android in general (so far, but I'm more than happy with it to date).
Here's a link to an installation guide:
http://wiki.openelec.tv/index.php/Dual_Boot
I haven't tried it (no need so far) but, as it will install on pretty much any PC I might build one in the future just to try it out.