mantucket - 1:57 pm on Jun 9, 2010 (gmt 0)
one thing I notice over just the past few days is that my GWT reports TONS more 'crawl errors' of many more types!
My site is fairly large, 325k pages with 250k of those indexed (per GWT sitemap stats) so I bet Caffeine enabled them to spider/analyze the whole thing faster which is good. It's also a long-tail site that I previously thought was high-quality & trusted - but got entirely dropped from rankings/traffic. So if I can figure out why Mayday suddenly reversed my quality/rankings, hopefully caffeine will help recover it faster.
OTOH, I notice a long lag in the issues reported under Page Speed, but that's still in Labs, maybe it isnt running off Caffeine.