Its slightly misleading propaganda from the Apple fans.
As I understand it, it you run a non-tablet app on an Ipad, you get, as barky says, a little display with huge black borders, completely horrible.
However that's not the case for Android. Android apps aren't (generally) programmed for a specific resolution, they work with what is available. So if you have a higher resolution, it shows you more data. e.g. instead of showing you 3 lines of text, it shows you 6 lines of text. It doesn't show you 3 lines really big, there is no 'scaling up' as you might imagine, or how Apple 'scale up' to support ipad 3 resolutions.
Of course, this does rely on developers coding their app semi-competently, but the bar for this is far lower than requiring the app to be coded specifically with tablets in mind. Its like worrying if you get a bigger,higher-res monitor for your PC, will MS Word be useable.
in short, its really nothing to worry about. I've not found a simple app that doesn't work fine on my Nexus 7, and many look great.