Get the Facts on Firefox, Opera, and Internet Explorer

I switched to Opera a long time ago, since it was version 3.xx

What I liked the most then was tabbed windows and open window in background (this feature was the most important one for me).

Other things I like about Opera (some were added in later versions improving it a lot):
* I get more information when a page is loading than IE gives me - if that progress bar can be called information
* a lot of keyboard shortcuts
* true window resizing
* mouse gestures - I found myself trying to close other windows using mouse gestures
* quick switch on/off for images
* user mode/author mode (very useful for badly designed sites)
* search on google with and "address" like 'g search text'
* fit to window width

I like Opera the most because it has a lot of options and useful features and allows you to do a lot quickly and easily. My browsing experience is very pleasant using Opera and I can't say the same thing when I use IE (for some of the sites that doesn't work in Opera). I just hope that Opera will gain sufficient popularity to make web developers take it into account everywhere.