I have the 32gb model and I will say that I am very pleased. As others have said it makes a great companion piece of gear for web surfing etc.
However, I also found that I can replace the steno pad I normally tote around everywhere with me at work. In the office I deal with a lot of different projects, people and departments which require changing gears quite frequently. I have found that I can take good notes (that can be searched), manage my pending job tasks (Things is a great app, esp if you are into the GTD method), get my email (great exchange integration),and to make sure I'm not double booking myself on appointments( outlook calendar sync). Having one thing with me that allows access to basically everything is very handy.
The battery life really is 10+ hours. I calculated approx 6.5min of use for 1/% of battery life.
There are lots of great applications. As the market settles and people have some time to work on the apps, I think they will just get better with time.
With the keyboard in landscape I can type nearly as fast as a regular keyboard. However, the keyboard in portrait for me is basically useless.
If I had to complain it would be lack of an FTP client and lack of wireless printing.
I also am beginning to see the limitations of just wi-fi. At the house and at work I have wi-fi that is easily accessible. I do think that if someone is on the fence and really plans to use the device away from the house I would get the 3g model.
Overall I would give it a 9 out of 10. I do really think that this device has the potential to cause a paradigm shift in the world of personal computers.
Just so I don't sound like a giant fan boy. I am a regular user of Microsoft products. I work for a software development company working in an all Windows environment. I always have been and more than likely always will be a PC user. I just think that Apple is really on to something with the user experience and interface.
Also, if you don't know already iPhone OS 4.0 will be out this summer which will include multitasking(only supported on the 3gs + devices), a unified inbox for multiple mail accounts, and the concept of folders. Just to name a few new things.
Billyp