I've used them as the driver in tube amps, in place of 12AU7. 1950s Sylvania shiny black oval plates w/ D or horseshoe getters were the best (neutral and incredibly dynamic with a great midrange), but then the later dark gray and grey versions of these same plates are a lot less musical. RCA's of any era are pretty consistently good, and on the warm side. The oldest RCA "winged" plates (?) from late 40's early 50s are the sweetest sounding, but hard to find, especially with low noise. Tung-Sols (shiny black oval plates like those Sylvanias) are quite good, but a bit on the bright side. I remember GE and Japanese 12BH7 as being serviceable, if not spectacular. Haven't tried any pinched plate variants.
I can't overstate how much I prefer any good 12BH7 over 12AU7, when that sub is possible. I hate that 12AU7 is so ubiquitous in 2ch audio gear. My first experience was doing this sub for the driver slots of a Heathkit W5 pair, and the difference was massive.
Some of these tubes took a HEAVY load in the gear they were used in, so you're more likely to run into dog tired 12BH7 tubes than usual for 12A*7 variants. And they're also much more problematic for slots sensitive to microphonics - same gain as the 12AU7, but with much larger plates (similar issue with vintage 6SN7). Trust your seller or be willing to take a chance. Agree Andy at VTS is great for sourcing reliable 12BH7 tubes. I also like Brent Jesse but haven't bought 12BH7 from him.