Congratulations to the Dojo team in getting 0.9 out! It is something that I have been looking for. Alex Russell showed me some significant improvements comparing to Dojo 0.4 a while ago (much smaller footprint, 10X performance improvement, etc). Now these guys have delivered it! See the release note for details.
I did some study of Dojo 0.4 a while ago and posted my thoughts here
Dojo Footprint and Ajax Performance Recommendation. I’ll try to find some time to do a similar study on Dojo 0.9 to see whether/how much improvement 0.9 is bringing us.