i'm not too familiar with chase, so i'm interested as to what others have to say, but i've used citi thank you for quite some time now, and feel it is somewhat limiting. like you, i like to have the flexibility, and TY just doesn't really allow for that.

i did sign up for the amex PRG, it has a $175 annual fee, but with a 75k or 50k sign up bonus, it isnt' a bad deal at all. you get additional multipliers for gas/supermarkets/air, and if you spend 30k/year, you get an additional 15k points i believe.

it's been working out for me so far, but i've started to use different cards for different purposes to maximize my return. if you don't want to deal w/ multiple cards, this one isn't a bad option by itself.

Edit: wanted to add that AMEX membership rewards has a ton of flexibility. you can transfer to airlines/hotels for redemption as well as redeem for gift cards directly from AMEX.