kossglobal the screen type it really depends on how you design the game. but most non iphones (Android) are 16:9 res so letterbox works without black box because they are mostly the same aspect ratio
Since I didn't understand very well those tutorials that teach you how to support multiply screen sizes, I'm using scale outer and making sure that everything important is shown.
Ashley's tutorial says that any 16:9 resolution is ok to use. So, if I use 1280x720 it should fit perfectly on any device? It doesn't happen as I've noticed too.