I don't consider sideloading to be on the same plane as rooting. Probably this poll should have 3 choices: rooting, sideloading, and walled garden. The lovely thing is that Amazon left a gate open in that walled garden. So I've sideloaded Getjar and some outside apps. I've got GO Launcher so I can switch between Amazon's Home Page and the Android-look Home Page easily, depending on what I'm trying to get to. And that's part of what I'm loving about the Fire vs a Nook Color rooted with an N2A card (which I also have) - much easier to tap an icon than to turn on & off to switch between modes.
So I too voted that yes, I'll be sideloading, but I'm not rooting.