There is not much to say for the tubes. They all sound similar. All sound bad. Not worth the money that you would stand on them. When they were released, tube hardware was not considered high-end. Now, since the tubes are used in high-end by audiophiles having them is just not a good match for the amps. Sell, sell, sell.
I tried Sylvania, RCA (a bit better than the others), Baldwin, GE, Motorola all with the same results.
The only exception is RCA clear top – they don’t come with black plates and they sound quite good.