the sidebar was the best feature in Arc imo. I gave zen a shot just because of that and it was not a great experience to be honest. First, migration was buggy, then the sidebar lacked some basic features like renaming the tabs even though it looked similar. Nook seems to follow in the same footsteps I just hope that they nail the sidebar like Arc. Tab management is a mess and this has so much potential. All the best to both Zen and Nook.
the only missing from the sidebar thing is Library as a central place to manage downloads, spaces, and history. and although the downloads window looks a bit unsexy, it's totally enough
