When should you buy software from the Mac App Store, and when should you buy directly from the developer? Here is a list of what needs to be considered when you're buying new Mac software.

Developers can make the decision very easy for you. Apps like and , for example, are now available exclusively in the Mac App Store; if you want to buy them, it's your only option. In other cases, app pricing may differ ever so slightly between the Mac App Store and directly from the developer's site, since Apple requires that all prices end in .99: TextExpander costs $34.99 in the , but $34.35 on the ; BusyCal costs $49.99 in the , and $49 directly from .

On other occasions, though, the price differences between a developer's Website and the Mac App Store can be significant. Apple's own Aperture 3 costs directly from the company, but just $79 in the --a $120 difference. (The $199 version from the Apple Store is a DVD copy with paper documentation sent to you. The $79 version is a download, with only in-app and online help. Is it worth the extra $120 to have the installation DVD of Aperture 3, especially given that you can re-download the app as needed from the Mac App Store if you buy it there? That's for you to decide.)

The savings increase dramatically if you use more than one Mac. According to , "Apps from the Mac App Store may be used on any Macs that you own or control for your personal use." Legally, you need to purchase the $79 to use the software on more than a single machine. With the Mac App Store, however, you can purchase , , and for $15 each--and then use them on any Mac linked to your personal iTunes account.