We swapped our AMEX Ultimate cards earlier this year to AMEX Discovery cards which have no annual fee but do retain a points earn. That was a much better option for us as we could then spend our $450 however we liked and the other benefits of the Ultimate card just lacked any value for us.
A few years back AMEX dropped the 2 free QF lounge passes we had routinely used for DOM flights, you can't use the AMEX lounge passes for DOM flights because they are situated in INT Departures, the AMEX lounges in MEL and SYD are not good quality anyway and since we fly J internationally, we always have access to the QF lounges. Plus, as noted by others, AMEX charged more than QF for the same flights.
Also it wasn't user friendly in that if you booked with the $450 credit for a single pax and later wanted to change it, you could then only use the credit for that same pax i.e. you couldn't use it as part of a booking for 2 pax. Overall the Ultimate card just wasn't user friendly for us.