Some differences between Flow and Blokk: • 3 weights/styles • Variable width characters • Improved line-height (to match SF)
Not sure about what Blokk supports but Flow will have: • Extended Latin character support (Update on 24th July) • Cyrillic character support (Update on 24th July)
Font-size works fine for me, not sure what's your issue. But hey, I like Flow, having round corners is useful.
It's just that concept is the same as Blokk, which was done 4 years ago, so "that" deserves credit.