I am not familiar with these models, but I would say if piano is strictly your pursuit weighted hammer action and 88 keys are very important. You want it to play as much like a real piano as it can.
If you are recording into a computer with DAW software, then the onboard sounds are not as important if you plan to invest in a software computer program.. I invested in a relatively inexpensive controller, a Privia 150 because I could care less about the internal sound engine...I simply wanted the piano keybed and feel. I could then take the money I saved on a high end rompler and buy piano software.
I have never really fell in love with the sounds in most romplers, even the high end ones.
If you go the route I did you will need a fairly robust computer and Ram.Preferably a seperate hard drive from the one your OS is on. I'm not talking the best of the best...a middle of the road quad core with maybe 8gb of memory and tweaked for music.
Given a less than workable computer another option is to buy a modeled piano, not sampled, but modeled using data from real pianos. Uses less ram and memory and some of them sound pretty good. Pianoteq comes to mind.
The sounds in romplers are usually measured in mb not gb and it shows.I like the pianos on the Yamaha Motif best but they still fall short of sampled and modeled pianos.