We rode a Burley Duet for about 10 years (we still own it.... saving it for when our girls may visit with their husbands). A little more than a year ago we bought a Santana Sovering. We loved it from day one. Mostly better handling, responsiveness, and ease for climbing. We did not ride test a carbon frame bike, after reading Tandemgeek, Zonatandem, and others comments, we wish we did. If only the stock market had a nice run up.....