+1
I have 1 of each and love them: 650s on my custom steel Rodriguez
700s coming on my soon-to-be here "replacement" Seven (titanium)...yes, there's a toe overlap consideration on the 700 wheelset and I'll have @10 degree of slope on my top tube, but I had it on my previous Seven (destroyed by a car crash) and it was not ever an issue. I was aware that 3 things need to happen, at the same time for a toe overlap calamity to happen: very slow speeds, hard turn of the front wheel and front foot in wrong position. I had that bike for 4 yrs and it never was an issue, so I don't expect with the new one either.
I'd only suggest that you pack or carry at least a replacement tire as I had a surprise blowout while on a training ride once. Not in Seattle proper, but out in the Carnation valley to the East; I tried to boot it but it wouldn't hold. Luckily a friend's husband was providing support in his pick-up, so he took me to 5 different bike shops in every town all along our century route; no one carried 650s, so my ride ended too darn early that day. That's the only time it happened to me, but I learned my lesson f'sure and since the Rodriguez is now my commuter bike w/a rack, I have a replacement (folder) tire stowed/along on every ride now.
The other incident with 650s was on the Montana AIDS Vaccine ride in 2001 and my friends tire blew while we were sitting near our bikes at our lunch stop. The ride mechanic did not have any 650s and, since we were in the middle of the ride week, she had to get someone to driver her into Bozeman
(1.5hr drive off the route) in order to buy a new set...whew! (She also now carries at least 1 back-up tire EVERYwhere!).
It would be great if 650s did become more commonplace, in order to avoid those exceptional situations that stop rides completely, but it's a caveat to plan for taking along anything that you might need, that's all.
Tailwinds!
Mary