This program offers you an easy and quick alternative to checking your Instagram account with your default browser. The application is very simple to handle, gives you access to what's new on your Instagram feed, and runs on your Menu Bar without using many CPU resources.
After you log in to your personal Instagram account, you can start checking the latest photo and video uploads, like and comment on posts, and access other users' profiles. What's more, you can alter your account information directly from the program's interface.
Another advantage is the auto-update of your Instagram feed while you're away from your Mac or working on a third-party program.
Personally, I wasn't too happy about the fact that I had to make an in-app purchase in order to have access to all features. Even enabling the option to show App for Instagram's icon on Dock requires this in-app purchase. Nonetheless, after paying this small fee, you can define a global hotkey for revealing the app's interface, enable Desktop mode, and hide the program's icon from your dock.
All in all, I think you can find better solutions for managing and monitoring your Instagram account. Other programs similar to App for Instagram don't require in-app purchases and offer you all the features you could possibly need.