I would suggest that the ascend acoustics sierra 2ex are on the inefficient side, so that may be a consideration. I found the Sierra 2 a little boring, I guess I prefer a little more personality in my speakers, Ascend usually voices their speakers boring ruler flat, but that may be your thing...
I had the exact same experience with the Sierra 2’s and RAAL towers. They measure extremely well and nothing was wrong but nothing stood out for 2 channel. Never excited me. Much like Benchmark, they seem to be designed/built to measurements to a fault. As such, I think the ribbon clarity and ruler flat neutrality of the Sierra lineup is great for AV/Home Theatre. I now use their wall-mountable Sierra Luna’s/Duo in my small 5.1 room - for that purpose they fit my requirements perfectly.