I bought the Flight Deck. A bit pricey at $100 (LICKBIKE.COM) but I LOVE IT!!! I like the ease of installation, and the fact that it tells me what gears I'm in. I'm a single rider with a new tandem, and I never knew how often I looked down at my gears to check gearing until I got the tandem. The virtual cadence is fun: It works most of the time, and is great fun when going down hills coasting, and seeing cadence rise to 208 RPM. And the shift button on the STI levers is, as we bikey nerds USED to say before it was, "like, OVER, Dad!"...WAY COOL.
Bob Van Siclen