Opera is the greatest thing since perforated toilet paper.

By providing only the basics and letting the user add whatever features he wants (if available), the Firefox team may seem to be catering to the minimalist, but Firefox, without addons, is still slower performing in almost every way than Opera. If you want a real minimalist browser that is light on its toes, go for Chrome.
I use Opera mainly for the tab features (duplication, follower tabs, cascade, tile etc...), the Trash can/undo, the mouse guestures, and the quick find/history search. Which if any of these exist in FF are almost impossible to find and or use. I have gotten so used to not caring if I accidentaly close a tab anymore. It's a very freeing experience.
Before some FF fans get all huffy I know you can duplicate tabs and undo closed tabs but they might as well not exist.
"As it turns out Firefox has the capacity to
duplicate copy tabs. However I discovered Atlantis while trying to find where Firefox referenced tab
duplication copying. I found it by searching their online help database for 'copy tab' -- not 'duplicate tab'. So to
duplicate copy a tab you hold Ctrl while clicking and dragging and dropping the tab. If you let go of Ctrl before you drop the tab it won't work."
"Undoing closed tabs in FF we again run across a function that, because of obscure placement or bad implementation, is a rarely used feature (Ctrl+Shift+T). Weird button combos aside, Firefox will let you undo tabs through the history menu. History>Recently closed tabs> select the tab you want to restore. However it being under two sub-menus and the fact that they collapse every time you restore a tab means if you want to restore multiple tabs you will be spending more time getting back there than actually getting your tabs back. As mentioned before, your next option is to use the shortkeys. Position your fingers over those buttons. Not very comfortable or easy to use. I have large hands and I can barely reach all three buttons with one hand causing enough discomfort to warrant using both hands. Your final option after closing a tab in Firefox is to right click on the tab bar > undo close tab. However, this brings us back to the most annoying tab bar in all of browserdom, where yet again if you have only one tab open there is no tab bar. So you were browsing with two tabs and you closed one by accident. Now, you can't use the most practical form of restoring your tab because the tab bar you need to click on disappeared because the Mozilla masters decided that the top 20 vertical pixels of the current page are more important."