Originally bought mine for solo or duo playing out, but then I conviened my too-big guitar group and have little real need for it, right now. But that will change again, eventually.
So now I use it primarily as a rehersal tool- record sections of a song (or the whole song) into it and drill myself on learning the passage/lick, for instance. Mine came with some backing tracks already on it (I put more, and will add still more) which I let rip and play over with either guitar, slide or harmonica when I am home and working on my chops.
And it is coming in handy for this: my guys seem to be shying away from a particular song I want to bring to the group- I am using it to help me capture me playing ALL the different guitar parts in Jackson Browne's "I'm Alive;" once I have them all down and layered, I will play that recording for the group and say, "Now, see, I learned EVERY part of this song. If I can do it, you can, too. Now let's play." (The looper is allowing me to not have to play each part for the entire song, just a loop I can punch in and punch out as needed, onto the actual recording on my DP-01.)
I dunno what you guys are complaining about, it not being stereo. If I "needed" a stereo output from it, I would just patch it thru my RP-7, and choose a stereo patch on the RP-7- say, "Panning chorus." But, really, I'd rather spend that extra time playing, than rigging, so mono works fine for me.