I follow Many Moons method but with EZD3. I took a song I'm working on and experimented with Bandmate. It was pretty simple, took about fifteen minutes, and the result was interesting.
Using MM's format, I already had a four bar drum groove selected and duplicated throughout which I felt was a good start for the song. I had already recorded the instruments and played to these drum loops so I should have played in time. This isn't what Elwood did, playing free time, but should work in the same way. I used the rhythm guitar part, dividing it into eight bar segments, the largest that EZD3 Bandmate uses (I think?) and kept them in verse-chorus-etc . Then I drug the track segments one at a time into Bandmate, clicked twice, and got a list of suitable grooves. In the interest of speed, I used the first suggested drum pattern (there were many choices) and returned it to the DAW in an empty track. There are options to tinker with the loops in Bandmate but I just used the first suggestion as written.
In twenty minutes I had a pretty useable drum piece. It's not what I would have programmed, but that's sort of the point I suppose. With minimal editing I probably wouldn't think twice about using it. It's difficult to say, when I'm playing and recording, I'm not the best judge of what sounds right sometimes. I won't be able to say for sure until I live with it for a while.
I'll try to get a couple decent mixes up tonight and post them to see how they compare. First chance, I'll try with an acoustic with no click track and see how well it works. it seems like something worth exploring.