Dave, by power and slam, I mean that the BAT's bass region is more prodigeous.....it feels more powerful. The ARC on the other hand, goes just as deep in the bass, but is tighter and better defined, so it seems to be 'lightweight' compared to the BAT at first listen.
By more refined and articulate, I mean the ARC also has more extension and definition in the high's. The BAT may sound warmer, the ARC may sound livelier. The choice is yours. All around better choice? No. Better for some? Yes.
You need to decide what musical values are more important to you, bass and warmth, or detail and definition?
Sadly, even at these prices one has to make choices.
Happy hunting,
John