Charles,
As for emotional involvement, they are just two different flavors. With either amp, I could listen for hours at a time and feel emotionally involved. If I can close my eyes and imagine being at the Blackhawk nightclub, or some other venue, then my system, including my amps, is doing its job for me.
As for realism, like I said, my OTL amp was noticeably more full bodied and rich in sound, which I really enjoyed, but the OTL was also somewhat diffuse and obfuscated when compared to the Franks. For example, with the Joule bass notes were fatter, drums had more weight, and cymbals could waft in the air forever, it seemed, but I was not hearing things I can hear with the Franks. However, I was using negative feedback a bit with the Joule. I liked the sound, but was it realistic? I thought so when I owned the amp (I Iisten to a lot of rock and a fair amount of jazz), but the Franks brought a different point of view.
I do feel that with the Franks, I am getting more of the inner detail of the music. I will say the Franks are noticeably more realistic with piano notes. My kids played piano, and what I hear through the Franks is closer to what I heard them playing. This is probably more than you wanted to hear. I could go on and on comparing these two fine amplifiers, both of which are immensely enjoyable in their own way.
When it was the time to choose an amp, I went with the Franks, first because they throw off very little heat, and second and more importantly, I am very happy with their sound. I went through several amps during the course of a year in search of a replacement for the Joule amp, and it took the Frankensteins to finally find something that I was happy with. I also found full range speakers that work exceptionally well with the Franks, so I get to experience something like the full bodied sound of the Joule, combined with the traits of the Franks that I like. All that said, I would like to own another OTL amp in the future. It would be great to have the option to again experience two very different yet enjoyable sounds.
Tom