Figured I’d chime in. “Devoted fan” of Becoming a Supple Leopard and The Ready State in general 
. I’ve been using his Virtual Mobility Coach for a month and have been pretty pleased with it, as I’ve had a twisted pelvis for several years that has gotten to the point of fatiguing my back so badly during cycling (triathlon actually) that performance began declining. The app has mobility prescriptions for body area, mobility tests, and pre/post sport specific warm ups and cool downs. Over the course of the month my power balance has slowly gone from 55/45 from the functional leg length discrepancy to between 52/48 and 53/47.
I briefly looked at Retül and it appears to be a significantly “lesser version” of the Virtual Mobility Coach. That said, if someone does not have known issues and just wants to restore general mobility, Retül may be enough. Subscription for VMC is $160/yr, which is more than reasonable - but at that price I’d be certain I wanted to use it before purchasing. He does have a free 2 week option, but that’s a very dumbed down version and more comparable to Retül than the full version.