Re: DR-880 Dr. Rhythm
I don't have that one. I have the much older BOSS Dr Rhythm 660, which, by the looks of it is a bit simpler than what the 880 is like.
For me, I found the buttons and small screen too fiddly, and the result was, that after the novelty of the toy wore off, programming the thing was too much of a headache for it to be worth it to me (a non-drummer, afterall.) I tended to use the presets exclusively, which got pretty boring pretty fast, especially since there were lots of "strange" (to me) presets which were not that useful, and only a few that fit with my kind of music. But was still better than nothing at all.
I would suspect you'll likely end up driving it pretty much exclusively via MIDI from the computer, and basically just using it as a sound module and ignoring nearly all the controls on the front panel for the most part, except perhaps for switching between drumkits and controlling the volume. That's how I ended up eventually using my DR660, though nowadays the sounds within it are a bit outdated and one-dimensional sounding, the 880 is undoubtedly better in that respect simply by virtue of being newer.
I guess what I'm saying is don't worry too much about any features it may have apart from the sounds which it can make, because likely you won't use anything but the sounds.