Depending on how good your computer is, Opera will buckle sooner or later if you have very demanding pages. That does not usually happen with Chrome (unless you have a huge number of tabs, which doesn't usually happen to me).
Our usages differ quite significantly. Why does that make Chrome stone-age?
"You can also use ghostery (an extension) to block all these resource-consuming background scripts, just in case you have reached the limits of your hardware."
Plugins that are available to pretty much every browser aren't a compelling argument for superiority (http://www.ghostery.com/download), just developer awesomeness. I notice that under Opera it says "/Almost/ full detection", so it's not even as fully featured as on other browsers.
If you're allowing plugins, I'm not sure I can think of a feature in Opera that you can't acheive in Firefox. But of course the argument is that Opera gives you all of them out of the box (whether you need them or not), in which case you can't use widely cross-browser plugins to try and bolster your argument.
"And by the way, one last thing. The default option for Opera is to restore your tabs from your last browsing session, which was not the case for Chrome and Firefox last time I checked"
I almost never want to restore the last session, and when I do Firefox and Chrome (and Opera if you change the default settings) give me the option to without forcing it upon me.
A lot of the defaults in Opera seem to be geared around managing a large number of tabs. I don't have a large number of tabs. I have a few windows with max. a dozen tabs each and I use bookmarks and other tools to manage things I want to keep around long term. I know lots of people who do the same. Yours and my use cases differ. That doesn't make Opera or Chrome or Firefox poorer, it just means different design trade-offs have been made.