Fyne or Great?

I owned the 501SP for about a year. Used them with a AN Cobra and a Luxman 550AXII. I tried the Union when I had these. The Zu is definitely a more lively sounding speaker with more dynamics and energy. The Fyne is more laid back, maybe a bit more mature sounding, but I found it to lack a bit of enthusiasm. It could sound too polite at times. You might have a different experience with your F8, and I think you might be okay power wise.

The 702 would probably offer more than the 501SP I owned so you should take my preferences with a grain of salt. It's a well made speaker, although I was a little disappointed that everything that appeared to be metal was actually plastic, but that's minor, and common among makers.

Appreciate your observations.... it's a crap shoot on selecting/replacing a speaker if you don't try it in your own system.  Agree with your comment on the Zu being lively and do appreciate this about the Zu.  I might be patient and seek out a Zu Soul 6 since I enjoy the Zu sound.  

I did find the Union a little on the lean side for my tastes but I know lots of people love them. They also lacked some of the clarity I've come to know from previous speakers. I tried them because they sell direct and I believe at one point they used that in their publicity, no middle man, etc so better value. I somewhat agree with that. I'd like to try the Union Supreme in my room. There was a Soul 6 on the mart, might still be there.

Best of luck!