Lorraine:

No, regular science diet is not a good food, and their natures best food is even worse, not only do I know this simply by looking at the ingredients, but some of their representatives said so when this new line first came out.
Vets are not nutritionist, they know very little about companion animal food, and half of what some of them know is completely incorrect. Sorry but that's just the way it goes. Once in a while you'll luck out and find one who actually has studied it and knows a lot.

Get him off that food (it's basically junk, no offence to you, I'm just saying, since you asked.) I could explain to you the many reasons why it's junk if you would like me to was well.

Here are the best foods IMO:
Felidae
Solid Gold
Natural Balance
Wellness
Chicken Soup for the Cat Lovers Soul
Pinnacle

Other foods to consider:
Evolve
Holistic Blend
Nutro Natural Choice
Natures Variety
Sensible Choice

And then the low end of foods I might possibly consider feeding if I could not get any of the others:
Maxximum Nutrition (Walmart)
Annamaet
Bil-Jac
Artemis
AvoDerm
PetGold
Azmira
Excel
Eagle Pack
Hi-tor
Lick Your Chops
Natural Life
Natures Recipie
Nutro
Premium Edge
PetGuard
Precise
Purina ONE
Pro Pac
Pro Plan
Royal Canin
Triumph

Good luck! And remember just because you buy a more "expensive" food does not mean it's more expensive, in the long run they can cost the same, if not less then the junk brands. Please don't buy Eukanuba or Iam's.
I hope you 2 can find something good that works!