There are enough lengthy reviews out there about the Transformer already. Most have pegged exactly the pros and cons of this device. No need to restate what is already out there. I've been waiting for a long time to get something more portable than my laptop and never thought the Netbook really solved anything. The Asus Transformer w/ the keyboard dock in my opinion is the future of mobile computing.
Battery life is long enough for easily being used all day without being plugged in. I can use my keyboard to take notes, quickly respond to e-mails, etc. I disabled the track pad because I think it's too easy to accidentally touch and move your cursor, so I use the touch screen and the physical keyboard. In this configuration it is just like typing on my notebook. Keyboard is easy to adjust to and very responsive.
Honeycomb 3.1 is great. I can plug in my digital camera, download pictures and even upload them right to Picasa. I use Dropbox to manage any files I need on the go and usually use PDFs in Dropbox with the ezPDF app to view and markup. With that app I simply open my PDF, can read and even handwrite notes using my finger or capacitive stylus, save the file and the next time I'm at my desk I have my PDF with my handwritten notes on it. This is what having a tablet is all about!
Surprisingly few have commented on the business apps. Calendar and e-mail are great with great Exchange support. I've had no problems and find that I like Honeycomb's clients better than Outlook 95% of the time. The bundled office software is not a full featured word process (no spell check and multi-level outlines aren't the greatest) but it is probably the best mobile office suite available, and you get it for free with the Transformer.
For taking notes and writing simple documents it works great. Contrary to what I've read other places I have been able to view and edit Office 2010 docs (.docx, .xlsx and .pptx) files. Overall, it's a great tablet. Exactly what I've been waiting for. Haven't unlocked my laptop from my desk since my transformer best tablet for kids arrived.