I have a Roland GR20 with the GK3 pickup, and would recommend it for ease of use, ease of installation (pickup to guitar) and tracking speed. You no longer need a keyboard to get reliable, fast-tracking MIDI.
As for sounds: The GR20 comes with a good selection of very realistic samples, including acoustic piano,Hammond B3, a lot of exotic instruments like sitar, and a very convincing alto sax. The tenor sax sounds artificial, but the alto is amazing. Don't take my word for it: Go to the Roland Site and listen to the demo.http://www.rolandus.com/products/productdetails.aspx?objectId=592&ParentId=53