Once you add in CSI shipping (although who only buys 1 thing from CSI?) it's pretty much even.
Lately I've been pointing a lot of people to CSI but most bow out due to paying for shipping. $13 for the X-Wing Force Awakens set was a great deal, but once someone sees $19 after shipping it seems like a mediocre deal at best.
But I don't mean to get in a pros/cons of shipping and CSI tangent here. That's a rant oft left to other threads.
Ascendency at Amazon for a 1-off purchase is a great deal.