Sure, Reynolds makes high quality CF forks. But, if you buy one used, from a stranger on ebay, you'll never know how durable it is, because you don't know what kind of use or abuse it's seen. Bad installation, overtightened or wrong stem or internal hardware, poor cut on the steer tube....all these things could ruin the strength of the fork.
I'm a tightwad, but I'd save up and go for new on these. That way, you get them with the right installation instructions and warranty. Plus, you'll be able to register the serial number with Reynolds, so if they do have a safety recall on your fork, they'll notify you.
After all, forks, along with stems and bars, are parts that you don't want ever to fail.