The Android GUI
For most operations, I prefer the Android GUI, which makes its commercial debut in T-Mobile G1, to the GUIs in BlackBerry, Windows Mobile, Symbian, and iPhone. iPhone's inspiration is evident only in G1's flick-to-scroll and long press gestures, both of which are well integrated.
Dedicated menu buttons below the display and on the keyboard pop up unobtrusive, connect-sensitive menu icons in a strip across the bottom of the display. Tapping one of the icons either performs an immediate action specific to the application, such as showing your present GPS location in Maps or pulling up a settings panel that you exit with the back button. The back button also either closes the foreground app or returns to the previously displayed screen, one of Android's few GUI ambiguities.
As you have probably seen by now, program icons are on a slide-out tray rather than cluttering up the home pages. You flick the app tray out and scroll through your apps in a non-hierarchical icon grid. Clicking an icon takes you to that app, or you can flick the tray back in to reveal one of several home screens. You can selectively drag app icons onto the background of any home screen to gather applications by purpose or any criteria you choose.
Android's standard PIM applications (e.g. calendar, contacts) are adequate but uninspiring. However, Android's Java 2 Micro Edition API is well appointed with device-specific features like multiple fonts and rendering styles that make rich application development a breeze, so much so that Android's standard PIM apps can be seen as placeholders. What's more, a built-in Apache Web server, Google Gears, permits the on-device use of client/server Web applications with server-side scripting, making HTML and CGI the quickest route to custom apps.
As unimpressive as Android's PIM software is, its browser, which is also built into Android's mail apps, is absolutely stunning in appearance, operation, and functionality. Android's browser is nothing short of a work of technical and GUI art, Android's killer app, a natural hybrid of a mobile and desktop browser. It is sublimely tunable through a wealth of options, but not so many as to cause confusion. The top feature is scalable text, which automatically rewraps as you zoom or change display orientation. Unlike iPhone, every page loads at a readable resolution and skips straight to the text in any page where a textual layout is present.
You can select a single-column mode that turns a page of HTML into a view that need only be scrolled vertically. You can navigate freely around the page and return to the formatted text column by tapping on a paragraph. Through settings, you can also switch to a desktop view that permits free navigation, aided by a whole-page view that allows you to select any screen-sized portion of the page. The browser takes advantage of the navigation trackball to highlight selectable fields, buttons, and links sequentially. The highlight is drawn as an easily-seen box. When a text field is selected, there's no pop-up, on-screen keyboard to obscure the display as there is on iPhone and other keyboard-less handsets. You swing out the real keyboard and continue viewing the whole screen.
To speed rendering over slow connections, you can disable images on the page. Because the browser is used to present HTML-formatted e-mail as well, the safety and privacy of optional image display is extended to the mail client, an option that iPhone lacks. The e-mail clients, one each for Gmail and generic POP/IMAP mail, are exceedingly well done. Gmail, Google Talk IM (which integrates with other IM servers and protocols), and over-the-air sync of contacts and calendar utilize Google's free services. On your first use of the device, you create a Google account or configure an existing one. Did I mention that it's free?