This article helps you determine what would be the best printer to suit your needs between the A2 Epson P800 and the 17" Epson 4900. There are a few key things you need to consider first to help make your decision - the size of prints you want to do, volume of work you will be printing, available space in your work area, and of course overall cost.
My general thoughts on the two are that unless you are doing a lot of printing, the P800 is almost always the better choice for most people.
The P800 is very well built, versatile, very simple to use and significantly better with sheet printing than the 4900.
If you really do want to do roll printing, I think the 7070 is a vastly better choice than the 4900 as roll printing and bigger prints go hand in hand.