Nielsen’s latest US consumer research has found that Apple’s App Store has an 84% satisfaction rate with its users – the best of all its rivals, although Google’s Android Market isn’t far behind with 81%. The survey is worse news for BlackBerry, whose App World store only gets a 58% satisfaction rate. Nielsen also asked people how many apps they have on their phones. The average iPhone owner has 37, followed by Android users’ 22. By contrast, BlackBerry owners only have an average of 10 apps on their handsets.