I recently bought the Apple iPhone 3G from my local mobile operator, used it for a week and found the iPhone 3G strangely "anti-social" for a modern 3G mobile phone:
It can't forward SMS messages. It can't send SMS messages to a predefined group of recipients (contact group). No copy and paste functions. No MMS messaging. No 3G video calling. It won't let you share documents and media files via memory cards or Bluetooth.
However, unlike other phones and PDAs, I found the iPhone 3G very good for Web browsing due to the large touchscreen and speedy 3.5G mobile Internet access. The iPhone 3G Web browser still doesn't support Flash and client-side Java, so I wasn't able to log in to my banking Web sites.
The new GPS (global positioning system) feature in the iPhone 3G works surprisingly well. The GPS was able to lock in to my location quickly when I tested outdoors in Singapore and Sydney, seemingly faster than the GPS in my Nokia N82. Using the built-in Google Maps with GPS on the large touchscreen feels very comfortable.
I'm impressed with the iPhone 3G's support for geotagged images and the ease of uploading images to the Internet. When you snap a photo with the built-in camera (which is only 2 megapixels, disappointingly), it captures the GPS coordinates (assuming you have GPS reception). With a few taps, you can upload the geotagged photo to Apple's MobileMe online service and share the photo. Click here to see my photo of the Sydney Opera House. When you mouse-over the photo and click the "i" icon, you can see that the GPS coordinates (latitude, longitude) were captured.
The iPhone supports an SDK (software development kit) for building custom iPhone applications. I expect to see many useful location-based iPhone applications that will take advantage of the GPS.
In the meantime, I'll stick with my Nokia N82 as my primary phone. I'll use the iPhone only when I need to browse the Web on the move (e.g. for e-mail) or when I'm lost in a foreign city.