Our Calfee Tetra will be 2 years old tomorrow. As of yesterday we have ridden it 10,279 miles in 7 different states. From a design and manufacturing standpoint there have been "0" problems with the frame and fork. The only problem that we have had was when we picked up a foreign object in the chain that caused the rear derailleur to get into the spokes and bend the rear hanger. The local shop was able to straighten the hanger and chase the threads.
I have made several changes in the past two years, new Shimano Ultegra cranks, Gates CDX belt drive, Dura Ace caliper brakes, stoker bars (carbon in place of aluminum), longer 35 degree stoker stem. We now have three sets of wheels and and will be getting a new rear Spinergy when it is available. We started out with Bontrager wheels, then upgraded to Topolino wheels and when we broke the spokes in the Topolino we bought a set of Spinergy wheels. I have used HED 3 wheels on my road bike for several years so I put a HED 3 on the front of the tandem. The rear Topolino has developed cracks in the rim so it will be replaced with the new Spinergy 43mm deep rim wheel when it is available.
We are still very happy with the way the bike rides and handles, and hope to put another 5,000+ miles on it this year.
Would I buy another Calfee? Absolutely, I am mentally planning our new bike, it will be a Dragonfly with 132.5 rear wheel spacing and I will probably go with Ultegra 11 speed and a version of a compact crank. That way I can use 1/2 bike shifters and 1/2 bike wheels. I am still partial to the HED3's but in 2 or 3 years there may be something else on the market that will strike my fancy.
For the time being we will ride and smile away the miles on current Calfee Tetra. It has proven to be a wonderful investment. We would not hesitate to recommend it to anyone who wants a comfortable, great handling tandem.
Wayne and Chris