They are both great toilets. Either would be a good choice.
I would recommend 2 things. You can go with the Eco model of either and still have the same great flush with 1.28 gallons of water. I would recommend also getting the Sanigloss finish as it aids in keeping the bowl clean. Low flow toilets do have a skid mark problem with some people. I haven't experienced any problems with my personal experience with the Drake though but others have.