> It has problems, especially with scripts. There are apparently simple > pages which will eat a third of a CPU, continuously.
In the past, I have foolishly let my computer sit overnight, with FF open to a site which (it turned out, on later examination) continuously cycled video ads. I noticed the next morning that the room was 20 degrees Fahrenheit warmer than normal, and the computer had not gone to sleep as it should have. The processor had been maxed out all night long, loading and playing video ads. This converted my low-powered laptop computer into a very effective little heating unit. Since then, I have started using Adblock and Noscript together, and shutting down FF when not actively using it, which avoids this "heating" problem. Now, I have to temporarily enable between 20 and 200 domains every time I do anything. I can't imagine what the www will be like in another 10 years...