I spent a good couple hours playing around with the B3K and the Vintage yesterday and have some thoughts. My disclaimer: They are both new to me, arriving just last week, and so far just playing around with my rig only an not in the mix. My rig is Puma 900 thru Baer ML112s, BTW.
First off, They really are different flavors good. I cannot get one to sound exactly like the other, which is good, right? I mean it wouldn't make to much sense for them to cover the exact same ground. From my pre-purchase reading, I was thinking the vintage would be an always on subtle effect to vintage up your tone, which it does great, but with the drive up it can get nasty. I mean it can get dirtier than I expected and least IMO can add more dirt than I would need for an always on effect. For me, the best tones from the vintage are with the drive around 50% and the ERA almost all the way clockwise. To my ear the ERA knob acts kind of like a vintage tone control or passive tone control where the highs are rolled off when set counter-clockwise. It may be a more complicated design than that, but that is what I am hearing. With my tweeter-less ML112s the effect of the ERA from fully counter-clockwise to fully clockwise is pretty subtle, with counter-clockwise having a more vintage tone and the clockwise having a bit more open sound.
The B3K is just a nasty good drive overdrive. I know nasty is a relative term and while I can't really compare to other overdrives the B3K just sounds more metal than the Vintage. I know Spencer said it was not scooped , but when compared to the Vintage it has more of a scooped tone. The Vintage seems to emphasize the mids more and the B3K seems to work more on the low end and high mids. Where the Vintage sounds warmer the B3K sounds more metallic. The Vintage is like a classic tube amp being pushed and the B3K is a more industrial metal sound. Vintage = John Entwhistle, B3K = Justin Chancellor.
While there are similarities between the two pedals, they work differently and I cannot get the BK3 to sound like the vintage. Some have said it is redundant to have the B7K and the Vintage, but to get close to the Vintage tone with the B7K you would have to bump the mids but even then I am not sure you could obtain the warmth of the Vintage. Now, you may like one more than the other or only have a use for one or the other but I am pretty sure there will not be a Vintage setting on the B7K.
I could easily keep both of these pedals on my pedal board and not feel like it is redundant. The Vintage can warm up a sterile rig and give you a classic tone. The B3K is well suited for modern metal and running the B3K into the Vintage is just sick sounding. The way the more scooped sounding B3K interacts with the mids on the Vintage is just great to my ear. If I were playing more or if I needed to warm up my clean tone I would keep both, but since I am not I am going to move the vintage. I like my clean tone and it is already a bit warm and I like the metal sound of the BK3. Great pedals Doug and Spencer!