I have just got my hands on one of these having had my curiosity aroused by some You Tube videos. I initially went for the Boss DD-500 because the two guys from Andertons who do the reviews raved about it, hinting that it was better than the Strymon Volante that they use and that I'd never heard of.
These reviewers are often wrong as I found out to my cost, as they coaxed me towards buying the Boss, but after a bit of digging and checking, the Boss is kicked fully into touch and I bought the Strymon Volante.
It's only been in the house a couple of hours, but it's not leaving my sight !