Pricing seems to be consistently about $400 per person. For a couple, $800. In a way, this is like packaging AA's (standard) Five Star Service into the ticket. For $350 for the first person and $100 for additional persons on the same booking, one gets Flagship First check-in, an escort, and Admirals Club access (but not FF Dining). For a couple, $450. Given this, FF Dining would be $350 for two -- $175 each.
But, if one is flying in Flagship Business, one will have access to either the Admirals Club or (regular) Flagship Lounge. So, it's fair to ask whether FF Dining is worth the $175 per person pop. And, if one is Platinum Pro or higher, one gets to use FF Check-In if flying in Flagship Business. For them, it's even more of an apples-to-apples comparison.
Lastly, FF Dining is only available at JFK, DFW, and MIA. LAX remains closed. And, while AA stated that it is temporarily closed and "will reopen soon," the staff at LAX say that it will likely never reopen (in spite of passenger volumes). Seemingly, AA's endless pursuit of cost cutting. Choose wisely.