Unlike the extra spit and polish applied to the OS on the HTC Hero and T-Mobile Pulse, the Galaxy uses a completely standard installation of Android. This has its advantages as it's familiar and also seems a little faster to use, but it's definitely not as pretty.
On the homescreen, you can horizontally slide between three desktops upon which you can place widgets (mini apps) as well as shortcuts to apps, webpages, bookmarks, and contacts. You get the usual Android choice of widgets - analogue clock, music player, photo viewer, calendar, and Google search box - while those apps you don't load onto the homescreen are stored in the slide-up menu at the bottom. You also get the usual slide-down notification bar at the top that keeps you up-to-date with downloads, emails and calendar events.
Google Mail, Google Maps, YouTube, GoogleTalk, and Calendar all come preinstalled, of course, and they work as well as you might expect. Likewise, the web browser is superb, rendering full web pages properly and quickly, though it does occasionally get image sizes a bit off when zooming in and out and judders a little when scrolling through highly graphical pages. Other POP3 and IMAP email accounts can also be set up, though sadly the accounts don't merge into a single mail folder like on the Palm Pre.
Nevertheless, with the Android app market on hand to give you access to thousands of useful apps and fun games you'll seldom be wanting for functionality.
Call quality was good though it seemed that adjusting the volume mid-call made the phone hang-up. We are in a bad signal area, so it could have been dropping the call for that reason and just been a coincidence.
The Samsung Galaxy should have been a class-leading Android handset with its good quality camera, superb-looking screen, and masses of storage. However, a misguided collection of physical buttons, a poor keyboard implementation, and the lack of multi-touch result in a frustrating user experience.