I'm loving this!
The framerate is *such* an improvement!
Also love the multi-word search. Integrated sign in and linking directly to edit.aspx from the synther is an interesting but probably necessary play for getting people to really engage.
I love that the geotagging now uses Seadragon for the maps. I, for one, would like an option in the editor to use overhead view as the initial visibility although that does create a question of which image to display for those who need to install Silverlight.
The thumbnail view of the map to the right of the synth in place of the globe icon is interesting. I like it but the colours begin to be a bit conflicted between the Photosynth motif, the global imagery, and the photos in the synth.