I think the disc brakes a good choice as the front canti brakes shudder or squeal even with great care in adjustment. Good choice for commuting vs. CX racing.
I got a 57cm, I am 6'2" with a longer than normal torso (when I got a back x-ray the technician said amazed at how long my spine was for my height) and shorter than normal legs for that height - i think my standover inseam is 33" The poprad has longer top tube than seat (i.e. ~58cm top tube for 57cm frame)

Al