All of my road bikes use 10-speed cassettes these days. Chains seem to wear out a bit quicker, but as far as I can tell they're just as reliable as anything else. My touring bike uses a 9-speed trekking crank (48/36/26) along with 10-speed FD, RD, chain, and cassette (12-27). One caveat: I use Shimano STI brake/shift levers rather than barcons or DT shifters, so I can't comment on shifting performance.