The Goldtec hubs are only available in unfinished aluminium which seems like a terrible idea to me. Look out for corrosion/oxidation on the surface if you're going to use it in the winter, or rain, or even just outside.
Not used a front hub as rear, but have used a VeloSolo cog on the disc side of a 135 mm hub - very nicely made, easy to swap and worked well but didn't have it long enough to see how durable the cogs are. The converted front hubs are a nice clean solution for a bike with rim brakes.
Currently using a Surly Ultra New disc/fixed hub, seems nicely made if a little heavy.