Shahinian , Arc v Obelisk

I am looking for one of these Shahinians for my system . originally it was an Obelisk but have not found one affordable on Ebay yet . I understand that the Arc has a different sound , and that shahinian's are all like that a little different not just in gradation . The arc's are a little smaller and a little cheaper but are they as good or nearly so ? what are the differences ? Do some of you prefer the Arc to the Obelisk or visa versa .
I have room for both sizes but might move to a smaller place in the city at some point . looking for either will double my chances in finding one .

Thank you all .
unless your room is huge, the arc will perform just fine across the bandwidth.
Can't speak to the Obelisk, but I own a pair of Arcs. Have them on the short wall of my 24 x 11 room, only 12" in from the side walls and 20" from the front wall, and it puts up that Shahinian "wall of sound" quite well. From what I've read, you couldn't do that with an Obelisk, they need to be out into the room at least 4 feet. Also, the Obelisks apparently demand an amp with a lot of power/current. The Arcs, on the other hand, are an easy load, and have great synergy with my McIntosh MC250.