I have found it easier to cash in hotel points than miles.
I have the Hilton Amex card. They have several levels of cards; with varying levels of benfits. I have the Aspire card. I believe with any of the cards if you spend $40k per year you get upgraded to Diamond (their highest level).
Our goal is to maintain Diamond and we concentrate our card spending on the Hilton card.
With Diamond you get complimentary room upgrades, a free breakfast or a $15 person food credit, free or preferred parking. The staff works harder for you & is more accomodating when there is an issue. They are more apt to give you a dollar credit or point credit if there are problems.
With a Marriott affinity card we have Platinum status, without a spending goal.
One of these cards gets us National Car Rental Executive status, where we can pick any car on the lot (don't have to go the counter) at a mid car rate. You get free days based on the volume of rentals. Again Executive status gets us better service when there is a problem. We had a problem with one rental and wound up getting a full refund & a $200 credit on a future rental.