I'm not a Jadis expert but will share what I have heard.
At a dealer with MBL transport/DAC, Jadis JPS2, Defy 7 MK IV, NBS cables made actually the B&W Nautilus 801 sound decent. Swapped out the amp for MBL and music was gone.
At an acqaintance's house: Forsell table, Counterpoint pre, Defy 7 (I think MK III because it was in 1995/6), Watt/Puppy 3/2 & Ref 3A Royal Master. Phenomenal sound.
Defy 7 is musical, has tone, dynamic and a bit of a sunny day glow. Tube amp classic!
Caveat: prone to reliablity problems for that vintage, in fact on one listening session one channel went out and the fun had to stop. As well you have to buy 12 matched 6550s tubes and has to be tri-matched (ask Upscale Audio). The Ferrari of tube amps!
I am a c-j owner but not the Prem 140. I can say it will probably have the house sound of being musical with good tone but higher resolution than previous c-j amps but maybe not more than the Prem 8A and it will be easier to bias and maintain. I like to call c-j amps the Lexus of tube amps!