Jeremy, the Ensemble Dirondo is very detailed, very dynamic, with a great bottom end and terrific layering in a large soundstage, but has a "cool" overall sonic signature.
The AA Capitole MK 11 offers the above with somewhat less details and dynamics, but offers a "warm" overall sonic signature.
There both great sounding CDPs, offering different perspectives on the musical event they are playing, so it would come down to personnal taste and system synergy.
You might want to take a look at a thread I started entitled: Reference DACS: An overall perspective, that talks about two different "flavors" in DACS and CDPS. The Ensemble is a #1 and the Aero Capitole is a #2. Both of these categories are described in detail on this thread.