I've had my Mk3 "PDJ" for 3 weeks, it's done 455 miles so far (longest single ride 102 miles). I thought the first thing I would need to change would be the saddle (san marco rolls), but I have now fallen in love with it, along with the rest of the bike, and if and when I wear it out would replace with another of the same.
The only modification I've done is to shorten the steerer tube (this could have been done at the time of being built if I'd known how high I wanted it). I hve ridden over some quite rough roads and the wheels have stayed perfectly true. So while they may not be "the best" in terms of componants they are well built.
I had been looking for my perfect bike for 18 months, I have now found it and consider the Mk3 to be the best of this type of bike for the money.
Roger.
P.S.
I did make one other modification, before riding any distance I fitted quick release safety clips to the front mudguards, which I think is remiss of Thorn not to fit them as standard.
Another thing I think would be an improvement is to have seperate eyelets for a rear rack rather than having to fit guards and rack to one.