Not saying one tandem is worse than any other, but my bias does show in my posting. I do not enjoy the slumbering ride provided by limited experience on our 'Dale, similar large fork offset to Santana. I am sure not nearly as comfortable. I do think that suggesting that someone whose back or arms ache after riding a Co-Motion or similar might benefit from a switch to Santana or similar oversimplifies the situation. Comfort is more about fit than geometry. Once up to speed a bike that fits will allow the rider to be more relaxed, releasing the 'death grip' and not suffer from soreness often misassociated (is this really a word) with bike geometry. I do not find myself constantly fidgeting with steering input, but then I am used to bikes with more trail, I do not feel like my arms or back have received more of a workout than the rest of my body after a tandem ride.

Notwithstanding market penetration, do you even think for a minute that geometry bias has anything to do with familiarity, age, bike handling skills, etc?

I am still just thinking out loud here and have no basis in fact other than limited personal experience, that is why I am asking.