Last year I sent a frame to East Coast racer James and he recently broke the rear derailleur hanger due to muddy course conditions. It's an easy fix with dropouts from Paragon Machine Works...the hanger will be replaced with a stiffer 7075 aluminum version. Over email I told James about our new Euro-style cable routing and some subtle changes to the lower yoke. As a racer, his feedback is very valuable to me as a designer...see below:
The frame changes sound cool. I noticed the Euro style frame on the blog this summer. Very nice frame. My older bikes [steel IF Planet X's] all have top tube routing. In all honesty, I dont think there is much difference between top tube vs. downtube routing. I've found that the collection points for mud are the brakes and front derailleur itself. The yoke dosen't catch any more stuff than other designs. I think the yoke design gives more clearance betwwen the crank arms, chainrings and stays towards the BB junction. I race in both the New England and the Mid-Atlantic areas. Mostly dry to damp conditions overall. When we do get mud it mixes with grass and makes things clog up quickly. That's what happened when I snapped my hanger. In retrospect, I should have swapped bikes midway through the race. Again, thanks.
Here's another useful thread on 'cross cable routing from the Mud & Cowbells site:
Which type of routing is better? Everything on the top tube? Ultimately it's the rider's choice and Ahrens Bicycles is happy to deliver your preference.