I am not a flute player (or just a bad recorder one) but as I meet many musicians who start using the Sylphyo, I could make some answers:

The horizontal / vertical position switch doesn't seem to be a problem. Setting the flute fingering on the Sylphyo allows flute players to use their usual fingering technique. Concerning the mechanism of blowing, Sylphyo's mouthpiece is quick to master and allows good breath dynamics: https://www.youtube.com/watch?v=wsQujn7dPY8