Shoulder the BMC - that chainstay/top tube cluster might feel pretty uncomfortable. Kona certainly knows how to build a 'cross bike what with Trebon and Wicks giving them feedback. Ridley is the world cup 'cross brand, but if you're not down w/ the European geometry (short top tube, crazy-high bottom bracket, tall stand-over heights) then their bikes really aren't for you. I like the Ridley's because with their short top tubes and tall head tubes they seem to be a good match for my proportions. I'd prefer a bit lower bottom bracket (hence why I'm in love with the X-Fire which is Ridley's new carbon design and has a slightly lower bottom bracket - I'm taking donations if anyone's interested). One other thing to consider, depending on your uses for the bike are horizontal top tube vs. sloping. Depending on frame size and angle of slope is can give you better stand-over clearance or make throwing your elbow through the main triangle awkward. Something to take a look at if you're test-riding bikes at least.