Of course, Android's an entire platform and, like the iPhone, a big part of the platform equation is third-party applications. Android's answer to the App Store is the Android Market, which lets you browse and download applications. The Market application is primarily organized into Applications and Games, each of which is divided in turn into sub-categories. At the top of the home screen is a list of featured applications, which you can tap on to be taken to that application's page.
Downloading an app is a breeze: just tap the install button and Android will tell you what resources the application requires (location services, for example). Once you've installed an app, you'll find it listed in the Applications drawer. You can manage your applications by going to the G1's Settings application, and tapping "Manage applications." Android tells you how much space each application takes up, what permissions it needs, and allows you to clear the application's default settings and data or uninstall it altogether.
The Market allows you to comment and rate applications, just like the App Store, but it does currently lack one thing that the App Store has in spades: applications that cost money. Right now, the only apps on the Android Market are free ones; that might seem great at first blush, but consider that it means that many professional developers aren't making their wares available there yet, which limits the catalog a bit. Paid applications are on their way, however, so this is only a temporary shortcoming.
Little things mean a lot
It would be easy to say that the G1's biggest problem is a lack of polish: little details that are rough around the edges, like the inability to type in portrait mode, or the screen timeout issues when you're on the phone, or the settings checkboxes that can be hard to discern if they're on or off. But little things add up: they're the ones that make us increasingly annoyed with our phone over time, making us feel like we're fighting against the phone instead of the phone helping us.