MOSH had become a headache of sorts for Nokia thanks to some of the unmoderated content, which resulted in legal problems and copyright issues. The Ovi Store, on the other hand, will be a fully moderated, Nokia controlled environment, like the Apple App Store and the likes.
The Store content will be heavily customizable and will be tailored to your needs based on your location and social preferences. There is a Social Discovery feature available as well with the Ovi Store, which will automatically allow content from your social networks to be prioritized and made available for download and repeat consumption. In short, localization and tailored content seems to be the Ovi Stores mantra.
If you’re a heavy MOSH user, you might as well have a last look at the store because there isn’t much time left now