I've got 7 or 8 Viprati pipes and he is the most heavily represented pipe maker in my modest little collection. They range in quality from 1-clover to Fiamatta grade. I really like the pipes. I think he uses superb briar, finishes it well, and I've yet to have one that's poorly drilled. I especially like the filter pipes he does, because I smoke 9mm filter pipes about 90% of the time these days.
That said, I don't think that his pipes hold their value especially well. I've bought 2 or 3 of my Vipratis as estate pipes for about 30% of their original retail value. So if you're looking for an investment, a Viprati is not likely the best choice.
But truly, of my 60-odd pipes, inlcuding Stanwells, Castellos, Radices, a few North American artisan pipes, I'd include 3 of the Vipratis among my 4 best smokers.