Back Ot! A Simpson chubby is a nice experience. However there is better out there. Too over priced, inconsistency in materials used and build of knots and finish of handles. On the plus side, you do get a lot of scene points!
If I was to buy one, it would never be new, it would be from someone who I trust so they can make sure that these issues don't exist. The above is from personal experience over many brushes (somewhere in the 100 region I guess).
IMO You can't go wrong with Shavemac. High quality finish of handle, very very well priced for such a high quality knot, no extra charge for a custom, great service, the list goes on. In fact I've had Bernd 'fix' some of my Simpson brushes which have had some terrible knots.