Pretty great so far except that unchecking the "Display total number of tabs above the popup icon" setting doesn't seem to stick. It turns off the popup icon for a while, but then stops working in new tabs, other tabs, or even the same tab if other tabs are closed or just switching to a different tab. The tab popup reappears pretty much the minute you do anything tab wise.

Another bug I experienced is that if you move the TabSearch button into the Overflow Menu from it's default position on the toolbar through Firefox's "Customize", and then use the hotkey to activate/toggle TabSearch, the cursor doesn't automatically focus on the textbox and you need to manually click it to start searching.