Unbiased? You'll find very few of those. Opera users are fairly passionate about their browsers. Those that don't like it, seem to be just as passionate about it. There isn't a alot of middle ground.
v7 beta, some quirks yet and I wouldn't recommend it just yet. It has more work to get done and about two dozen options are grayed out. Additionally, I just don't care for v7 - it's flash over substance and it moves Opera far into the page designers realm and leaves it's user first roots behind.
v6 Pros: fairly solid and mega fast. The biggest thing is the awesome page-to-page surfing speed. shift-control-click increases my surf speed 3-5 times easily over bloated mozilla and the clumsy in-your-face/hassled-by-the-man IE.
Page control: don't like our choice of fonts? extend thumb out from mouse and press the + key on the num keypad to zoom up the font size.
Don't like our color choices? Tired of eye bleeding pages? CSS squint factor got you down? Just press the 'user mode' (control-g) button to rip out the css at any time.
Really don't want to expose your self to, embedded flash (press f12 turn it off), GIF animations (f12 turn em off), embedded noises, popups, groans, or other nasty IE aimed annoyances? Just toggle it all off, kick back and surf.
Viruses on your agenda? 3 minor holes in the history of Opera and each were fixed in 24hrs. You are never exposed to the onslaught of nastiness and depravity that infects IE and puts your whole system at risk. Throw your system resource zapping web virus scanner away - Opera's got your back.
Opera is also the only browser to respect your surfing privacy by allowing you to turn off referral strings. I've had them off for years. It's nice knowing I'm not leaving a trail to private info just laying around on the web anywhere.
The need for speed: My morning run of news sites is 32 pages. One single click on my bookmark menu "open all folder items" and that book mark branch is opened in 32 windows while I make coffee. All loaded up and ready to read when I get back. All that, and no spammed out task bar too boot.
shift-control-click (open page in background) will redefine how you surf. Rattle off 10 clicks on a search result and start shift-tabbing through the pages while the ones in the background load - no need to set and wait for things like you do in ie/nn. Your always on the move with opera. The "
still loading" phenomena of ie/nn is gone. I can do more with a 56k line and Opera than most guys can with ie and a t1.
If there were anyway to show you or tell you how much faster and productive Opera can make you, Opera would be the #1 browser on the net - no doubt about it. It's a better, faster, safer way to surf. There is just no way to experience it short of really learning to use the program and surf in a new way. An hour won't do it - a day won't do it; but in a week the power of shift-control-click will show itself and you'll be hooked.
I've had Moz guys over here to the ranch and they leave with their mouths open at how fast an opera pro can surf.
In IE/NN, you read - you click, and you wait for it too load. In opera, you read, you shift-control-click, and when done, you go to the next page - no wait time at all. While you are reading, you are loading the next click in the background. Highly addictive.
Mouse Gestures are also highly addictive and super productivity boosters.
Some of the newer dhtml doesn't always work (it's what v7 is addressing, but it's not ready yet).
There are a few other quirks here and there with a few pages. Just about any site owned by Microsoft (aint that funny) is going to make you jump through some hoops. All the ms sites (I feel/know it's intentional) throw up something trying to slow down Opera users.
Basically, all the major sites work excellent with Opera.
For my money, O-v6 is the best browser ever made. It's mega fast, it's mega secure, and it looks out for the user first.