US is tough. Internationally I would give Hilton a slight edge with the many (good) promos, consistent upgrades and good lounges. Within the US it becomes more tricky indeed and it is IMO YMMV. The $30/36/50 'food' credit for 2 guests is not great, BUT, e.g. if you get an Impresario/FHR/etc rate where BF is already included, then you get another dining credit whereas with Marriott you get nothing. Also, the $50 credit at their higher end properties can go a long way. Marriott IMO has more lounges than Hilton (if that is important). I find Hilton and Marriott similar in terms of UGs in the US - both upgrade me perhaps 90% of my stays. Hilton is more of a '1 category' whereas Marriott IME can be much more significant, but unpredictable.