I already had an iPad 3. It's not like I'm talking out against something I don't have, and this is not even a problem with the iPad 3. It's a problem with the web in general, as well as other contents.
And no, they don't scale well. Especially not these forums. Specifically, the "Post Reply", "Edit", and "Quote" button that I'm looking at right now don't scale at all on the iPad 3, and they all look extremely pixelated and blurry compared to the texts.
A lot of websites are like that as well. It's a common technique to avoid rendering issues. Not everything is drawn on CSS because not all browsers handle CSS the same way, and not all CSS3 elements render properly in most browsers.
Again, this is not a negative for the iPad 3. It's a problem for web developers and app developers.
And trust me, I'm not the only one that feels this.