As opposed to many single road bikes, tandem's differ significantly from one brand to another in several ways. In terms of a comfortable ride, you probably want to consider a shock absorbing seat post as a simple and effective stoker solution. If you find the Cannondale jarring to the captain, you need to look at a steel (less expensive) or carbon fiber frame (costly, but lighter and more shock absorbing) frame. It's hard to describe the ride qualities of various manufacturers' products. However, among the two largest, Santana is often described as "stable" (less twitchy, less responsive), while CoMotion bikes are quicker responding, more like a single bike. From my recent experience, the CoMotion's do require more attention, but are also more fun (we just bought one). The least costly of these are in the $2000-3000 range, not much more than a Cannondale or a Trek. IMHO, considering how long you are likely to keep the bike, the difference in cost is well worth it. I have no experience riding a carbon bike, but these are generally much more eexcpensive (3X as expensive).