Without having a good tandem shop close, you may have your work cut out for you. Luckily, we have Mt. Airy Bikes about 40 minutes drive from my house. This shop is owned by Larry Black who is a great guy and combination bike historian/pack rat. He carries Cannondale, Trek, Santana, Burley, Co-Motion and KHS tandems. Plus, he has some older trade-ins and other odds and ends hanging from the ceiling, so if you are on a budget, he can get you on something.
I did not try a Co-Motion at Larry's shop. I did try a Trek, a Santana, a Connodale, a Longbikes (no longer made) and a KHS. I was a stone-cold tandem newbie at the time, and my stoker was a stone-cold newbie to cycling of any kind, so if I went back now, I would most likely work the bikes a little harder now and may notice things that I did not notice then.
My favorite out of the bikes I tried was the Longbikes. I think it had the stiffest frame. But, the KHS was 1/3 the cost and weighed about the same. One of these days, I will sell it to some other couple who wants to get their toes wet tandeming and move up. But for now, It gets the job done and we can stick with the B+/A teams as long as there is not a huge amount of climbing.