We suspect that, as with the iOS App Store, some developers will offer two versions of their software through the Mac App Store: the standard, paid version and a feature-limited "lite" version. But if you end up trying the lite version and later purchasing the full version, you're left with versions of the program, each likely using different settings files and data--a real hassle. We'd rather be able to download a traditional trial version and later upgrade, if we choose, using the Mac App Store's purchase process.

We've already covered the quite thoroughly, but it bears at least another mention here: If you previously installed a program that's now offered through the Mac App Store, and if the version number and bundle ID of your copy exactly match those of the Mac App Store version, the Store will display that application as Installed. Unfortunately, this mean that existing software will be automatically updated via the Mac App Store update mechanism--nor that your existing software licenses will be transferred to the Store. Apple should handle this situation better.

For starters, the "Installed" label for an application should differentiate much more clearly between apps that have and have not been purchased through the Mac App Store. If the Mac App Store sees that a non-App Store version of a program is installed, users should get a clearly labeled option to re-purchase that software from the Store in order to take advantage of the Store's multi-Mac licensing, simple updating, and lack of licensing/registration hassles. If a customer clicks the Buy button on such a program, purposely or accidentally, the store should warn the user, perhaps with a purchase confirmation similar to what we described above, about buying the same app twice.

Finally, as , you should be able to rate an application you purchased outside of the Mac App Store. It doesn't make a lot of sense to exclude a valuable--and potentially huge--pool of potential reviewers from weighing in with their two cents.