I'm hoping they will do away with the "you need to restart Firefox after installing an add-on". Chrome has been able to install/uninstall/disable/tinker with add-ons without the need to restart for years.
That and a new logo (tired of that fox) and I may give it another try.
The reason for the restart requirement is that Firefox extensions interact with the browser at a deeper level than Chrome extensions. Firefox does have a newer extension API called Jetpack that allows restartless extensions, but most extensions are written with the older (and more powerful) API.
