I tested 3 different 8x10's. A straightback, a new VR from Nam and the Heritage. We tried them with a Vietnam VR, a 73 SVT, a 78 SVT and the Heritage CL.
The jury were a guitarist (no preferences in advance on what to like), a journalist (this test is published in a dutch bassplayers magazine) and me (scared I had to spend 1400 euro's on a new Heritage 8x10 if mine would've lost).
Our tests showed that the straighback sounded the fattest, openest, most dynamic, tightest and the most punchy.
The Heritage 8x10 sounded a little muffled, but great nonetheless. When you push the mids, the ' problem' is more or less solved.
The VR from Nam sucked ASS. Thin, nasal.
BTW, I had a 78 towelbar that I didn't like as well. Thin, nasal too. Sold it as soon as I compared it to the straightback. Absolutely no match.
When I had to buy new, I'd go for the Heritage. I don't, so I have a straightback. Still the best.