It's a two part answer.
For poorly recorded or average recording quality music, I prefer my C607.
For the better quality recordings, the C807 (now the C809).
But I've now sold both pairs of the C807 I had. In favor of the Jamo C809.
The C807 and C809 sound nearly identical, with a bit more bass power in the C809. But the rest of the presentation is identical. So to help finance my new amps and preamps, I sold both pairs of the C807 and the C809 now stands in their place..
Just to clarify.
The C607's are wonderful with high quality recordings. But they straddle that line that allows poorly recorded material to be presented without being too revealing and distracting of the poor recordings and/or masterings. Of course, a recording that is just downright unlistenable will remain unlistenable on any speaker unless one could adjust the EQ a bit to help. But the C607 do have a way with that. Source components, preamps and amps in the chain, as well as room acoustics will also contribute to the final outcome. So one's mileage may vary, depending on those elements.
The C807 are a just a little more revealing and can be less forgiving of many poor recordings. Yet, some poor recordings still sound good enough so you can enjoy the songs, without irritating distractions. Depends on the recording itself and the other factors I mentioned above.
Ulitimately, I'm splitting hairs and really breaking it down to finer points, here. Because these Jamo speakers (both the C607 and C807) are still some of the most forgiving speakers I have ever listened to, while being amazing with high quality recordings. They have a sort of sweet presentation and deliver it with a dash of subtle warmth. But some recordings/masterings are simply attrocious and beyond help. With high quality recordings they really shine.
The C809 while being amost identical to the C807, do bring a few things more than the C807; than just bigger, deeper bass. They have this huge sound. Large soundstage, wonderful presentation of scale and presence; with a slightly laid back politeness to them.
Dynamics are very nice, without being over-the-top, kick-in-the gut ridiculous about it. Which in my experience over-the-top, kick-in-the gut dynamics and impact are good for wow-wee thrills when you first audtion a pair of speakers or gear.
But when you live with them every day, it becomes tiresome and bit absurd.
Because gear and speakers like that exaggerate dynamics way too much. Surely a personal preference/personal taste-based opinion.
Again, splitting fine hairs.
The C807 are one hell of a speaker. They will shock most people with their enormous, beautiful, musical sound and the amount of powerful bass they are capable of. And they can dig deep, too.
But the C607 do have this certain something....hard to describe, this addictive musicality to them. I find myself drawn to them often, despite all the other speakers I have in my house.