I was planning to get one of the new 'no lateral" Calfees this winter and transfer the compnents over from our Cannondale to it.
I've talked to Craig and followed the tandem forums for a couple years now,and I've not heard any first hand negative feedback about these designs from Calfee or the other builders that are using this design.Calfees suggest a weight limit of 360 lbs or other mods or a lateral design may be a better choice.You can discuss your weight with them and they will offer superb advice.They will also built it for your weight,if it is lighter.
The only negative I have heard has been from some guy at Santana,who has no such design to offer.His blathering makes me want to get one ::)Or get anything except a Santana.
Alas,my stoker seems to have quit and we are apparently out of the tandem riding business.