I've had bad luck with a lot of serfas stuff. The shop I worked in sold it and we had quite a few quality problems. On the good side, they have a really great customer relations/warranty person. And they always were good about sending replacements when the shop deemed that they were deserved (always remember that the shop doesn't loose any money on warranty stuff and for most manufacturers, it's really easy for the shop to warranty stuff. so when in doubt, ask the shop).

Given the choice I always chose conti over serfas.
Just don't ever buy the serfas Tuono (>30c slicks). I bought some for a really rough alleycat and flatted both before the end of the race.