From last May I've been buying F out right unless it's an E175/CRJ or a 321ceo on a shorter flight. The upgrade offers don't earn LPs and to me that's self defeating to spend money with an airline and not get credit for it.
During that time domestic F fares for at most mid cons were in the $750 to $1K range. Now they're up to $1.5K or more. IMHO too much money for a MIA/DFW type of flight. So it's back to either the upgrade lottery or giving AA more of my money and not getting LPs for it.