I can give you first impressions only as I have not giggled the BF/D800 rig yet. I'm in the middle of packing up and moving this week so it's been a bit hectic around here lately and I've only had the cab for a few weeks. (Bought used on TB).
It's definitely got a different vibe than my other cabs (2x Baer ML112 and 1x Berg AE210) as its emulating an old school sealed (although its ported) cab (which I've never owned). As such, there is a bit of sonic adjustment going on with my ears. I've made some adjustments to the eq on the D800 and the cab is more broken in now. Control settings right now are \ \ \ \ / ---> / , approx from left to right on the knobs with the BF. With my other cabs, the treble control is at noon. As stated above, it's thick and punchy and I would like another one too.