Well I have never own the NEX 5 or 7, so I can't really make a comparison. But as far as I know I haven't really encounter overheating with my NEX 6. I even use it to transfer pictures to my iPhone and never feel like its overheating. Of coz it depends on how long you have it turn on. I guess all electronics will do that (overheating) at some point even my iPhone does that. Hope that helps.