Hello...
I had also considered the Zoom R8, and the Tascam DP-008EX previously, but I think I liked the combination of features and low price of the Boss BR-80.
I might also have a prejedice against Zoom from my experience of guitar multi-effects pedals from the late 90s -- but that shouldn't really be relevant now.
After checking them again briefly, I do like the look of the R8, particularly if it works nicely with Linux. It also looks as though there is less fiddling with menus, which is probably more important than the extra features.
Does anyone know how well the R8 works as a USB soundcard with Linux?