I've used Science Diet for over 17 years, which is the age of my first cat, though she's not the oldest one in my clutter.  Everyone is very healthy, with nice coats, that isn't all fly-away when it's shedding season.  Only a few hairballs every now and then too. 

It's well worth it in the long run, and really isn't very expensive when you factor in the quality, and the daily feed requirement being less than other brands.  There is less poops and it is less stinky, so that's less litter usage too! 

If you get on the Science Diet program of feeding, be sure you sign up for deals and coupons...