One thing that confuses me about tabs on top is that it implies that everything below the tab is associated with that tab. Ok, I get that part. I watched the video by Alex Faaborg and it makes sense.
But I therefore expect that if I rearrange any items below the tab, such as customizing the layout by adding or removing buttons or moving the home button to the right side, or resizing the size of the address bar versus the search bar, that those changes would be limited only to that tab and be sticky for that tab. That doesn't happen and visually it's confusing. All of those elements are grouped underneath the tab and when I switch tabs, the changes are there too. Huh? It's completely counter to what I was expecting and doesn't make sense. The only thing that changes from tab to tab is the text in the address bar.
I would think this would be very important due to the ability to save app tabs. I might want to save an app tab to a specific site and have the navigation toolbar customized a certain way just for that tab.
Note: I'm using beta8 and haven't upgraded yet so maybe this bug has been fixed.