Importance:
MediumGoogleGuy provides his summary of the latest Google update. 
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GoogleGuy Says:
I'll summarize from my viewpoint. The mechanics of the switchover went pretty smoothly--about one data center per day. Things that drew comments included a somewhat higher level of flux than webmasters expected and a tendency for subpages to show up more where index pages had before. Most people noticed fresher data (both pages and backlinks), especially as sites that were too new to get picked up in the Dominic switchover were found by Esmeralda.
Experienced update watchers also know to look for what people don't mention as well. For example, during Dominic some people weren't getting toolbar PR measures for a few sites. I kept a list of sites where the toolbar indicator didn't list PR because of technical reasons like url canonicalization/etc. Happily, most/all of the sites that I checked were showing PR correctly for Esmeralda--so I didn't see a lot of PR0 questions this time.
Another thing that people didn't mention on the update thread as much this time was spam. That matches with internal testing for Esmeralda, and the spam reports we received. The number of spam reports for Esmeralda was lower than for both Cassandra and Dominic, for example.
There were still people who claimed that Google was obviously, undeniably, irrevocably broken. I thought that there were fewer of them--but they seemed to post more loudly to compensate. :) I think the tone of WebmasterWorld has been a little more strident lately (sometimes because of uncertainty, sometimes because newer members are getting a feel for the community here), but I take it as a good sign that right now the majority of the threads are people trading analysis about things like Flash, indexing latency and crawl IPs, what type of filenames are best (me, I'm partial to hyphens), and so on.
Overall, I'd say that the Esmeralda switchover went relatively well. Of course, people who have specific comments can always send in feedback via a spam report and mention "Esmeralda". Also, I liked the pre-post moderation system that Brett and the mods started testing. It helped to keep related threads together; the mods have also done a great job of keeping discussions on-topic over the last couple weeks.