Lots of people swear by those 45's. I've heard some that I thought were terrible, and I'm not sure why. A single 45 can't provide a lot of power, but it should sound good if used right. But I've heard a few 45 amps that were pretty unflattering to the tube, to say the least.Your amp sounds great. It sounds to me the way an amp should sound, so I'm giving it the nod for sure!
I think that there is something to be said of the active element chosen, but maybe even more by the configuration its used in. Your amp uses the 45 in a configuration that works very well. I know there are some that would say it's the 45 tube that does it. But I think it's the circuit your builder put it in as much as anything else.
You owned a lot of tube amps, and heard even more. What do you think?