Is a 7" screen big enough for web browsing?

Let me start off by telling you I have a 13 inch Macbook Air, which I purchased last year and couldn't be happier with it, It has great battery life, and is really portable and great for web browsing. I also own a Galaxy S2 (4.3 Inch screen), which is great for web browsing on the bus, however I do currently plan to upgrade to the next Nexus phone when it finally gets announced, but at the moment I am extremely temped to get a Nexus 7.

My only concern however though, is how good is a 7" inch screen for web browsing, is it big enough that I might actually use it for casual browsing over my 13" air?

Has anyone got a Nexus 7 or other 7" tablet? Its hard to know, despite how promising this product looks, if I need that third screen accessing the internet. Does it load sites like The Verge well enough and fast enough? The text size isn't a real issue for me, but does the layout load properly? The comments load okay? Ive looked at the 7 Inch tablets before, and always thought that the 7 inch size was considerably easier to hold, type on and carry round than 10 inch tablets. However now Im starting to wonder. Is the extra 2.5ish inches of extra screen compared to my phone make it justifiable for another purchase when I already have such a portable laptop? Or would a 10 inch tablet be better?