CloudFlare might hurt your SEO. At times cloud flare gets overloaded which means that the site goes offline. Not sure on the implications of this, depending on the error page returned.
Sega you`ve raised a good point.
Uptime is a proven SEO factor.
Here is a related quote from Google Webmaster Central blog:
"Once in a while we get asked whether a site’s visibility in Google’s search results can be impacted in a negative way if it’s unavailable when Googlebot tries to crawl it. Sometimes downtime is unavoidable: a webmaster might decide to take a site down due to ongoing site maintenance, or legal or cultural requirements. Outages that are not clearly marked as such can negatively affect a site’s reputation."
(Full post can be found here: http://googlewebmastercentral.blogspot.co.il/2011/01/how-to-deal-with-planned-site-downtime.html)
BTW: for uptime monitoring I would suggest using Site24x7.com.
In addition, while Google does indeed factor site speed into the equation, the honest answer is that it is not going to be the only factor in Google's Ranking Algorithms (nobody, save Google, actually knows what is going on entirely here & how they apply weight).
Agreed but, in this specific case, there is an official Google comment that states:
"While site speed is a new signal, it doesn't carry as much weight as the relevance of a page. Currently, fewer than 1% of search queries are affected by the site speed signal"
(Full post can be found here: http://googlewebmastercentral.blogspot.co.il/2010/04/using-site-speed-in-web-search-ranking.html)
This correlates perfectly to my professional experience.
Site speed is important, but only to some extend as its just one of 200+ SEO factors.
Site architecture (URL structure, canonicalization and etc), Content and Inbound links (in that order) are the real keys to success.