I've got the 830 (previous model) and I love it! It takes a little getting used to it when you go from a standard machine to one with a computer, but I didn't mind. The dealer I purchased from offers unlimited classes on it, so that was a major selling point for me. I went in a few times with it at first. She was very knowledgeable and helpful.
This was my 2nd Viking machine. The first lasted me about 16 years. I was sad to see it go, but thought it better to put the $300-400 repair charge towards a new machine because of it's age. I would happily buy another Viking!
The large throat area makes it much easier to quilt large quilts. So far the largest I've done was twin size. I plan to do larger, but by quilting in sections. It's hard on the shoulders to handle the weight. ;)
Is there anything in particular you want to know about it?