So agree with your last sentence in particular.
I HATE it when people say 700s are faster....I've MANY times in races had the fastest female bike split using my 650 bike. I also have had the fastest bike splits using my 700......

Here are some interesting reads:

http://www.rodbikes.com/articles/web_articles/bigfastwheels.html

http://www.rodbikes.com/articles/650-speed.html

https://secsmultisport.wordpress.com/2009/07/28/a-tri-bike/#comment-22

I don't disagree; it is irritating when people say this. I should have put "faster" in quotes b/c it's only true if people are really specific. Like HappyScientist said: 2 bikes running the same exact gearing, pedaling at the same rate, factually, the 700's will roll out more distance per revolution of the wheel.

That said, it doesn't feel the same to ride both wheel sizes. It takes less time to roll the 650's up to speed so they are quicker off the start. Going 20 mph is 20 mph regardless of wheel size. I just rode different gearing to hit that on the 650's than the 700's and maybe it takes me a second longer to reach that speed with the larger wheels. But the angular momentum of the larger wheel will eventually surpass that of the smaller one.

I'll add that I personally feel more stable on the larger wheels on hills. Specifically down them. 40 mph on 700's is less frightening to me than 35 mph on 650's. Something about the super high rate of revolution of the smaller wheel was unsettling to me.

Ultimately it's best to be comfortable on the bike. No bike or wheel size can be fast if the rider doesn't want to ride it. But after flatting the day before racking my Cervelo at Boulder (to which I traveled w/o a spare tire), and flatting repeatedly in Penticton (only brought 1 spare), both times on presumably new tubulars, I thank my lucky stars to be rid of 650 wheels. Many people hit spells of getting flats, but before that bike I never had anxiety issues over it.

(Edited to correct typos due to posting by phone)

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To breathe, to feel, to know I'm alive.