Bottom line: The more speeds the better IMO, as long as the equipment
is durable, and the 9 + 10-speed road bikes have been out there long
enough to be proven as such.
I'm riding a 7-speed cassette on Uma and confess to missing at least
one subtle gear somewhere towards the middle, so 8 speeds would
probably do me fine. But if 10 speeds is achievable, why not? The more
subtlety the better. You really have to put in some miles to
appreciate the nuances here, but they are real.
And, yeah, I agree, chains very rarely break.
LH