For me the AT-X is a great improvement even though I still love shooting my AT.
As an FYI, I ordered my AT-X from Mile High back in August 2021 in FDE. Found out they had blue ones in stock 2 weeks ago when calling to check status on my order so I switched colors. I got the rifle a week ago. Had them pull the 6.5 CM barrel for a $500 credit and got 3 internal weights and 4 external. Put on a 28” Hawk Hill MTU barrel I had cut a few months ago along with an APA Fat Bastard Gen 2 brake. They didn’t have the top rail or bag rider at Mike High but I found the top rail at EuroOptic along with a flat trigger shoe. No complaints with the AT-X today at all. Also, I idn’t sell my AT, but instead pulled the .308 barrel and put a Hawk Hill 6mm Creedmore barrel so I have a great backup gun! Ultimately the best choice is what you want to do with the rifle. Hope this helps and good luck!