Max never touched the Hills stuff, but would eat the RC pouches, the beef and tuna flavour ones went down the best. The dry was always a hit too.
Another good one, which is more of a pate, is Specific renal food, my vets used to order it in especially for me, and thats in foil trays.
The trouble is the renal food is quite bland, so cats can go off it quite quickly.
Max would tolerate it if I mixed in a same flavour senior pouch, it was quite easy to do half and half each mealtime as the flavours were quite easy to match up.
If renal food isn't eaten, then senior food with a phospherous binder is a good alternative, as Mark has already said.