NHT Xd's are absolutely fantastic. They are designed to present music without any coloration of their own so if you are into a "warm" Sonus Faber type sound then they are not for you.
My prior speakers were Dynaudio Confidence C1's paired up with a Velodyne DD-15. The NHT's stomp all over that combo in every category barring bass extension. The DD-15 could dig a bit deeper than the Xd subs.

