I can personally recommend Royal Canin Ageing 11+
First off, I didn't know Royal Canin Ageing 12+ before. I bought a 400g pack to try it out. The first time, my cat was so greedy for it that she threw it up later. But I kind of expected that, considering how much she ate at once. Now she gets it twice a day in small portions, instead of a 400ml food bowl for several days. Since then, everything's been fine. My cat likes it, and the can opener (me) is happy, lol.