I have been a little surprised at the people who didn't think this album was very good...
Indications of where RJD2 goes on Since We Last Spoke can be heard on his previous releases; it's not really as big a change as some would have you believe. He maintains a steady evolution from one release to the next, so you have to expect some growth and change in his sound with each new album. This isn't purely a hip-hop record, so purists will probably be disappointed. By expecting the same thing out of an artist or genre from year to year, purists are sometimes not inclined to appreciate change when it occurs. I.e., if you're looking for a record to spit rhymes over, this isn't it. This is listening music, and goes in the same individualistic and personal directions that any introspective artist does at times.
The album isn't very long, but it is long enough. A lot of good records would be great if a track or two had been cut, but this record is short enough to prevent you from thinking about that. You do, however, get the feeling that another track or two might have been a bit much.
Some tracks really seem a lot denser and more skillfully arranged than on previous albums. It's a little progressive, and not quite as accessible as earlier work, but not too much so. Still, I think this is what accounts for some of the negative reaction it has received...Since We Last Spoke does require attention and repeated listens in order to fully appreciate it, and while I don't think it is great I do think it is very good, thus four stars.