I had a few A-bolts. Still have one in stainless/synthetic, 7mm Rem Mag.
Just got rid of one in .300 Win Mag that had a Boyd's on it. I hated that stock. Fit and finish was fine, but in cold, frosty weather it got slicker than greased snot.
Personally, I really like the fit and feel of the factory Browning synthetic stocks.
I cannot offer anything on the X-bolt, never owned one, but I really like my 7mm A-bolt.