iOS because I want it to be secure and reliable. That and I've been roped in with too many apps to make a switch to anything else!
I'll mention my fav app too. CineXPlayer which handles 1080p MKV movie files, has DTS/AC3 support and syncs with IMDB for art work and metadata to all your movies. Just need iTunes to transfer the files from or to any machine so the device doubles as a USB storage unit for vid files too
