I've seen this video a couple of times and thought it was pretty interesting! A few caveats -- not all heads are connected to the same cab. This is especially important on the V4B sample clips, as it says it is connected to the V4 guitar cab, so that could make a big difference in the timbre...and it does seem to. What are y'alls thoughts? Personally, I think the SVT-VR sounds the best across the board (no big surprise there)! It sounds the most '3-D'. Although in fairness the earliest SVT they have is an 84 MTI (which sounds amazing still, especially distorted) -- no early 70s to compare the VR to. The B25 sounds great as well, and of course the B15(s). My biggest surprise is that I liked the SS B2RE over the SVT3Pro. The SVT Pros seemed to be voiced fairly dark, similar to the '84 SVT. I'm sure a bit of EQ could be more my style, but was pleasantly surprised at how warm the B2RE sounded. I played a SVT-450H a few times, which is the same thing, and I think with the 'vintage' voicing or whatever they call it, it sounds pretty good. Still no comparison IRL once I got my V4B.
The MTI and B25B were my favorites in that video. I had a B2RE and it's a great amp! I don't think it gets the respect it deserves and it's an American Ampeg to boot! Served me well and was bulletproof. The V4's always sounded killer but, I'm one of the weirdo's that prefers the non-B to B version. I can get more highend and mid punch in a rock setting. Best way to view this video is by imagining the era and genre each amp would be most appropriate for.