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 .

AB
Thank you all .