I have the following 7.1 system built out of Kefs:
Left/Right - KEF IQ9
Center- KEF IQ6C
Surround- KEF IQ8ds (dipoles)
Back Surround - KEF IQ3s
SUB - PSW 3500 (Pianno Black - great finish)
All driven by an Onkyo TX-NR905
I am really satisfied by the audio but I have no great experience since this is my first system that is above average consumer brands. All I can say is that my system still has a lot of potential since I have yet to figure out optimal settings, perfect positioning and I really need some work with the sub settings but I am getting there.
One more thing - make sure you have an amp of about the power of an Onkyo 875 if you want to make the most of your KEFs if you chose them. (This is also judging from my setup).
Other than that I have read great things about the Jamo D7 set but are they at the same price? Aren't they much more expensive?
I have used previous Kef Q series speakers the one before these iQ series and also used Jamo D7. I would go for Jamo D7 package. But I am here talking about movies and as far as I understand Jamo D7 is more towards movies then music. Good Luck.