I am a hardcore opera fan (i also use firefox thought). But I gotta tell you...

I think you just stay with Opera for like 3 seconds and then ditch him. I mean really the reasons are very balant.

• Lots of little UI things that can't be changed, like control-t making a bookmark, or control-w closing the current tab, but moving focus to the first tab > Go to Preferences > Shortcuts > Edit and you will see and advanced and complete shortcut editor. If that is not enough for you go to the standard.keyboard.ini and see the file to manually edit it.
• No nice extensions like greasemonkey, etc > Opera is not firefox, Opera don't have extensions we have them right in, actually no other browser have ever had extensions.
• Fonts didn't seem to look as nice > Get new fonts and use those ones, since is a css files you can put the ones that you need/want.

Ok first message I answer your doubts, this ones is to put the REAL advantages of Opera.

Forget about Powerpoint presentations, make your website one of it, using the slideshow power of powerpoint. You can use some special css tags (W3C standard) and render your site as slides.

Apply different views including a table-less layout so you can change those nifty IE coded sites into plain html clean pages.

Going through lots of pop-ups and XXX banners, just switch off the image viewing typing 'g'.

Browse your way through multiple tabs by clicking '1' and '2'.

Opera saves pages on a cache system that allows you quick 'back' button. It doesn't reaload the page so is incredibly faster. Use the back button on firefox and you get a pop-up do it in Opera and you get the actual page in less than 1 sec.

Big page... Linux user... quick search? use the vim signature '/' to do a qucik search within the page.

Opera display SVG -- expect improvements on this area...

Opera plays a big role in supporting handicap people so they incorporate voice and VoiceXML technology to read your pages, or render the aural css into a page... plus also have a high-contrast pre-designed layout.. and speech recognition (just say 'back')

So you have to open firefox and then click on a email and launches a different program in thunderbird... dude Opera has the thunderbird within... yes mozilla has it too.. but mozilla is a monsterly slow app. opera gives you the integration of mozilla with the speed of none...

Opera uses a sqlite database so your mail, bookmarks are infinitively faster.

Opera RSS feed Actually works... (it was the first one out there in a browser)

You got IRC integrated..

Download manager, resume available..

Contanct management is easy to browse since the sql lite engine is FAST.

Online notes.. this is one of the best things of Opera... I mean yes it is a bookmark but is more than that, is more like a bookmark within a bookmark it will not only send u to the page but also the section of the page. Is great for manuals and browsing through on-line docbooks.

F11 actually gives you a FULL SCREEN.

Mouse gestures are the best, since Firefox has 1000 mouse gestures extensions you never know which one you are using (if you are using someones else machine) with opera the commands are standard (learn once play them everywhere).

Plus they are the best, the back button in the mouse is fast as hell... eve when you have a form, it will go back and have the content in the form.

Opera is smart so in galleries it will recognize the next page even if you never load it so the forward is actually an extension of navigations.

You can easy configure and set RULES to the downloads, you can tell each file where to save, what to do, or from where to boot.

Opera DOES have limitations... and they are just 2
1) Javascript
2) XML-XSLT support