I mean when you differentiate browsers the main aspect you have to look at is their rendering engine.
Safari & Chrome = Webkit
Opera = Presto
FireFox = Gecko
IE = Trident
Out of these the worst browser rendering engine in the past decade was the trident engine used in IE6-8. IE is a little bit better but still not touching Presto, Gecko or Webkit.
I personally believe Presto is the most web standards compliment browser; but this is a double-edged sword because a good majority of programmers write bad/sloppy cod, so sites sometimes misbehavior and look funny when browsing in Opera.
I prefer Firefox(I'm dependent on certain extensions I've been using for years), as I had preferred Netscape in the late 90s. And here's an article explaining Chrome hogging your CPU's resources on Windows:
Peeking under the hood of Chrome browser reveals CPU hog | Computerworld Blogs