Depends on your flying pattern, what flights you want to redeem miles for etc. and which cabin. For instance, I'm US based FB Plat, most of my miles are redeemed on SFO -> Europe in J and most of my domestic flying on Delta is in D1/FC. On short stops (flights around west coast) I don't really care about upgrades (which actually wouldn't happen anyway due to wife having no status) and prefer 2 free checked bags for each pax on the booking.