I've flown a fair few hours now with SD running on an Asus 7" tablet. Can't fault it. I've flown 7hrs on the battery alone and still had a fair bit left.
It's cheap enough to leave dedicated to SkyDemon.
ASUS MeMO Pad 7 inch Quad Core Android Tablet Intel Atom Z3745, 1GB, 16GB eMMC | Laptop Outlet, UK