Bob, I tend to agree with your comments regarding the sonic's of the SED's and the Tesla's, both the JJ's and the pre-JJ's. The E34L also has a bit more energy and requires a bit more bias. I find the E34L's to be very sparkly (maybe a bit more than the Tesla EL34's). The SED's are IMHO more linear, certainly not bright/sparkly.
But the one thing that I have found undesirable in actual use of the JJ's or earlier Teslas - the tubes are not as reliable as the SED's. I've had several major failures with the Tesla's and I've had none with the SED's. I've been using them both for over 10 years.
Its probably only important for those with amps that don't deal well with shorted power tubes (which can take out resistors etc when they fail).
FWIW.
