I have been keeping an eye on Flock for the 1.o release to give it a whirl.  I am actually pleased with how well performance seems to be.  It even seems better than Firefox to me.  The theme looks great and works well for me.  All of my extensions installed except for two older ones that still work in Firefox.  Just about the only thing that still disappoints me is that there aren’t that many services built in.  I wish Flock would put in MySpace, Buzznet, Last.fm, Picasa Web Albums, and more.  I am sure that they are going to add more.  Perhaps they should create extensions for the different services so that you can pick which ones you want to be built in.  That way it can be customized for each user.  Overall, I am pleased with Flock and it is now my default browser until I find something wrong with it.  Maybe I won’t.  I am actually posting this entry from Flock right now!  Flock on, people!