Hi, relative newbie to this forum.
I purchased a B2C hub and Alex DM18 20 rim towards building a new wheel on a (formerly single speed) Swobo Folsom. LBS did the work building the wheel and installing. Total cost ~$145 parts/labor. Kept the old wheel as a spare (reused rear cog).
The hub works pretty well so far. I think its pretty easy to shift without engaging the brake though I have to plan ahead a bit at a stoplight to restart in LO.
With my 42t/18t cogs the hub runs at about 60 and 83 gear inches for low/hi gear. The 60 gear inches is fine for gentle hills, though I might change to 20t rear cog if my knees start protesting... Certainly the high gear makes the Folsom scoot right along - its fun pushing 20mph on a fat tire oversize BMX bike!
Will keep you posted as to the hubs performance through this winter.