It's a good pedal, but just overpriced.
If you are looking for "same as SD-1, but better", this pedal is pretty much a hit or miss. The new "Custom" mode sounds pretty good IMHO and fatter without sounding mushy or boomy, but it also kind of takes away from the basic gritty sound of SD-1. The grit which many love.
I would highly recommend you try this pedal before buying if possible, if you love SD-1 and think about upgrading.
Build quality is of course super solid, it's Boss. The pedal will live longer than you.