I have a mytype keyboard that i got from backing up the kickstarter project.
I would like to say that it is an ok bluetooth keyboard because you can fold it in half and bring it with you veverywhere. When folded it is almost the same size as the s4. I am also impressed because it has some speciallized keys made just for android, and i think it also works for ipads as well. The only drawback i found is the feedback i get when typing. It is made from silicone material and i don't like the press feedback it gives me ( i think this is just my personal preference)
I am right now looking for another bluetooth keyboard or keyboard dock for my note 10.1 and s4. If anyone is interested in swaping their bluetooth keyboard for mine, or buying mine of, feel free to pm me.