I don't agree with sitting up to climb. Some of my climbs I'm over 16 mph. And a few I top out during a all out effort with 21 mph average. On those high effort climbs I find that staying in the drops not only give me a advantage from being aero, but also by putting my arms at a better angle to offset the power I'm putting into the pedals.

While I don't always climb in the drops, I wouldn't sit up. The more I sit up the less power I can put into the pedals.

Of course I'm only talking about the climbs in the rolling terrain around me which is 20, 30 and 40 foot climbs at 4 - 6% grade. However even for a long continuous climb I still can't see the value in sitting up.