I don't feel frequencies are missing from the B3K, but it's strong point is definitely ultra present high-mids, so if you are looking for the "brown note"(notably Zeppelin) I would definitely recommend the VMT over it.
Here I have added bass guitar to a Helio Sequence song, and that upper mid presence lets the bass through the mix nicely without being obtrusive. It doesn't sound too "modern" but at the same time it doesn't have the "John Paul Jones Sludge":
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Here is why I love my B3K, though:
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There's low-mids here, but you probably won't notice them so much because I made the high mids ultra present. I haven't heard many pedals even come close to duplicating this sound. I guess this is probably closer to the "signature B3K tone" but I have always loved it.

I think the metallic bite contrasts nicely with a wall of dark analog-sounding synths.
The cut option on the newer version makes it even more versatile, but if you love low-mids over high mid presence, I would definitely recommend the VMT.