Browser for multiple tabs?
Yes, Firefox wastes too much space (especially when showing open tabs), maybe they fix that someday. In the meantime, have you tried with Chrome for Android? It has new gestures to switch between tabs:


  In Chrome for Android, you’ll be able to:
  
  
  Swipe horizontally across the top toolbar to quickly switch tabs.
  Drag vertically down from the toolbar to enter into the tab switcher    view.
  Drag down from the menu to open the menu and select the item you want    without having to lift your finger.