App for the phone (which OS)?

Hi guys, I hate smartphones. I got rid of mine about 4years ago. But I need to get a new one...
And now I want to get a smart phone, cause I feel I need the GB instructions with me in the gym. What OS is the GB app running best on?
IOS, Android, Microsoft? And if somebody has an smartphone OS that does not support of an Gymnastic body app but uses instead the website via the phone..., I realy would like
to know how well that works.

Hi Bjoern,

GB does not have an app at this time but a smartphone would still be handy for the follow along workouts. The GB browser works excellent in chrome and safari browsers on smart mobile devices.