Frame material is highly personalized and seems there are some who take to a specific frame material with nearly religious fervor. As much as I hate to admit it, some may count me among that number. With that said, I've only ever ridden steel and aluminum frames and have concluded that I like steel. Someday I'd like to try out a titanium framed tandem, but we're not in a big hurry since we just purchased our Bilenky 650B Constructeur tandem in June 2012.