A really really good comparison, and there's something for everyone in there too.
It gives a real world setting for everything too, as some preamps just sound pants compared to others, depending on the player and the bass, so much more honest than most test videos where everything is tweaked to sound as good as possible, sometimes, I suspect with external gear.
My favourites were mainly the Sansamp ones, the VT Bass mainly, but I will always have a soft spot for the BDDI, which is lucky as I have one
Eude