Bolder hype would likely not be the best phrase - there are lots of firms in the world who speak highly of their own gear, but over the years of following Bolder, and other AC manufacturers/members, I would that Wayne is a very modest guy - it is his clients that could (myself included) be guilty of praising his work - then again, I just like the sound of what I have bought, and I notice that a broad number of others who have heard my Bolder kit have ponied up too.
Having owned a stock SB3, with stock PS, what did it for me was the increase in "reality". Detailed but not sharp, tight but complete bass etc.
It could be the simplification of the circuit in the SB3. It could be the higher quality components in the chain. It could be the stability of the PS.
Honestly, I have no idea, but my system source remains the Bolder modded SB3, and after 2 years I know that Wayne's mods have progressed, but I am still very happy with the investment I made - and that is what matters to me.
I cannot speak to "the best digital out there", as I have never heard 80%+ of the other highly respected work. Nor can I comment on Linn being the #1 source company in the world, or where you would have gathered that.
Never heard a Transporter, but lots of folks happy with those too.
Try one!