CloudFlare should help your SEO efforts because we help speed up the delivery of content on your websites to your visitors. Please read Matt Cutts' blog on Google incorporating site speed in search rankings.
We did a couple things. First, we invented a new technology that, when it detects a problem on a site, automatically changes the site's CloudFlare IP addresses to isolate it from other sites. (Think of it like quarantining a sick patient.) Second, we worked directly with the crawl teams at the big search engines to make them aware of how CloudFlare worked. All the search engines had special rules for CDNs like Akamai already in place. CloudFlare worked a bit differently, but fell into the same general category. With the cooperation of these search teams we were able to get CloudFlare's IP ranges are listed in a special category within search crawlers. Not only does this keep sites behind them from being clustered to a least performant denominator, or incorrectly geo-tagged based on the DNS resolution IP, it also allows the search engines to crawl at their maximum velocity since CloudFlare can handle the load without overburdening the origin.
Your satisfaction is my success!