After owning this bike for 6 months i thought i would do a review....
Size is 19.5 and i am 173cm tall, this fits me perfectly although the seatube is a little taller than i would like ,and in the steep stuff the seat can bang me in the arse (????)forcing me foward a little more than i would want, i have remedied (no pun) this by using a 35mm rise bar instead of stock and cutting width to 760mm.
I run the bike in the steeper setting everywhere and the geometry etc feels balanced.overall im happy with sizing and glad i didnt go down to a 18.5.