Looking at the results with the page preview turned on I can't really read anything. I would expect that it could reduce CTR rates from people who would have otherwise bounced. There are times that I remembered the search phrase I used to find a site, but not which one I found my answer on. I can usually visually remember what the general layout of the site way. With the page preview turned on I wouldn't need to click each result till found the one I remember. I suspect this would lead to a reduced bounce rate along with a lower CTR.