It is actually an interesting question. On the one hand, I really like the fact that Bryston is offering board to update the SP-3 to more current technologies. However, when you upgrade, the part you are replacing effectively goes in the trash. When that is $100 worth of trash it is one thing. When it is $1000 or more of trash it raises the question of trickle down. Put differently, when is the overall user community better off with a steady supply of slightly outdated SP-3s available used at a bargain, with those wanting the latest upgrading their entire product?
I would guess that the new product version ultimately costs the consumer more, but brings new Bryston fans in through the used equipment market. Personally, I prefer the route that Bryston has taken, although it would be an even stronger preference if the updates were user plug-in replacements rather than requiring a reshipment to the factory and back.