Although I can't say this would have been my own most-longed-for collaboration, it's always good to hear Carrie - and in terms of likely impact and exposure it would seem a good strategic choice for both artists (Aldean for an album lead-off, and Carrie for a probable strong radio presence between albums).
As a song, I think the basic idea, of lovers looking back on a lost romance with a realization of how much it still means to them, is a good one (though not as strong as Brad and Carrie's "Remind Me".)
The musical style here doesn't do a lot for me, I'm afraid (I think the recent Need to Breathe duet gives a better representation of what Country Rock can produce) - but that is a personal reaction, and it is likely that this song will prove to have a more general appeal.
Of the songwriters, Kurt Allison and Tully Kennedy are members of Aldean's band. Lydia Vaughan, though, is signed to a company run by Brett James (who has been involved in several of Carrie's hits from the beginning). She was a member of an Alternative Rock band before concentrating on writing - and this could well become the breakthrough hit for her.
The song has undoubted hallmarks of Michael Knox, who discovered Jason Aldean and has produced all his albums. He often uses the power ballad style in his production, and has gained previous radio and award show success for Aldean's work, including earlier collaborationse .
I feel that Carrie's vocal hits the right mark. The song tends to be rather heavy on guitars and electronic sounds, which probably suits Aldean's vocal style. For me, Carrie's vocal adds a more sensitive and subtle contrast (which might have been less apparent if she emphasized a more powerful vocal line of her own). For me the best touch was that lilting passage she introduced just before the end.