Applications: The phone comes with a number of apps preinstalled--and you can add tons more via the Android Market. The versatile IM lets you configure instant messaging with AIM, Google Talk, Windows Live Messenger, and Yahoo Messenger. Because Android permits multitasking--and no app actually closes--you can receive IMs after you've left the IM app to browse the Web, for example. (With the iPhone, you won't get your messages if you leave the IM app, and you have to log in again each time.)
Mail from Gmail gets its own icon, but you can set up other POP3 and IMAP e-mail accounts as well, in just a couple of steps (the software automatically configures the server settings). The calendar syncs with your Google Calendar. I had no trouble viewing the various calendar entries I'm privy to, or adding an entry to my calendar, but I couldn't add an entry to other Google Calendars that I have rights to. And bizarrely, Android has no Google Docs support at launch; the only way you can access Google Docs is through the Web browser--a bit of a pain. You can view Microsoft Word and Excel documents through Gmail, but you can't save and view these docs through the Web browser. Similarly, you can open and read PDF files received through Gmail.
The Web browser handled much of what I threw at it, but it balked at some tasks (for example, it lacks in-browser Flash support). I missed having discrete forward and backward controls (you can go back only by clicking the universal hardware back button) and an option for offline viewing (as on a Palm OS-based Treo), but adding and retrieving bookmarks was simple.
The Amazon MP3 app is a useful alternative to iTunes, and music downloaded quickly and easily. I could queue up the DRM-free tracks for download, which occurred in the background as I did other things with the phone. Unfortunately, the selection is less extensive than the one on iTunes.
The music player application is easy to navigate, and great for finding and playing back music. Music sounded okay when piped through the built-in speaker (on a par with the iPhone 3G's speaker). But the lack of a standard headphone jack limits the G1's potential as a music player.
The camera app is a big disappointment. Though the device has a 3-megapixel camera, it lacks a flash, a zoom, and any controls for adjust image quality, white balance, or the like. There's no camcorder, either, though T-Mobile says that the imaging sensor can capture video if someone writes a video capture app and offers it on the Android Market.
T-Mobile's Android-based G1 isn't especially sexy or eye-catching, but it does a lot of things right. It's a strong first-generation Android device, but the absence of a standard headphone jack, a video camera, and Google Docs (and support for Word and Excel) at launch are notable detractions. Still, I would recommend this versatile phone over countless other smart-phones; Android's intuitive ease-of-use raises this phone above most Windows Mobile- and BlackBerry-based devices.