Tubegroover - I've had the opportunity to listen to several of the models in the Focal Utopia line. The store has always had the Diablo and Scala models on the floor and has always had either the Grande EM or more recently the Stella EM. I've heard the Diablos and Grande EM with both Krell and Aesthetix amplification. I've only heard the Stella with Aesthetix amplification. I've never heard the Scala's connected in the main system so I can't really say that I've heard them in a comparable way.
With the Krell amplification I really enjoyed the Diablo's paired with a JL Audio subwoofer the most. When the switch from Krell to Aesthetix was made I can't say that I've ever been as impressed with either the Diablo's or Grande EM's, but based on my most recently experience with the Stella's and Aesthetix there much be something else making the difference because it was once again an amazing sound.
I've actually heard several of the Chorus Series speakers connected to the main system when it was Krell based. The list is 706v, 816v and 836v (my speakers). I've also heard the 706v, 806v and 807v connected to the Aesthetix based main system. It's amazing at how good those models can really sound when given every opportunity to succeed.
By the way, I don't think the name JM Labs applies to any of the new speakers, it's simply Focal these days.