Surely someone makes a good-quality Complete wet food that's healthy, balanced, full of all the things a growing cat needs and relatively freely available?
Firstly, what you feed your cats, is completely on you.
There is no single solution which is the best.
Domestic cats have evolved over many years, to a point where they can now survive eating chips.
There was one cat owner on these forums, who had a cat live to 23 (which is outrageous) and he fed her mainly on canned tuna. So this might be a tip.
If you want the absolute best, you want raw meat, with added Taurine - cats need Taurine. Raw meat is better than any cooked alternative, including Appaws wet food which is the best wet food on the market.
Another point is: do not fall for marketing. Many people buy cooked wet food, assuming that it is better than raw meat from a butcher, just because it has a nice packet. Raw meat from a butcher, with no packaging, mixed with Taurine is much better than any cooked food (providing your cat can handle it).
I buy my raw meat from the following sources:
http://www.woldsway.co.uk/acatalog/index.html
http://www.naturalinstinct.com/categories/Cat-Food/
After you factor in p+p, raw meat from the above sources is expensive (around £6.50/kg).
After I switched my cats from Hill Science dry food to raw meat, my Egyptian Mau, who was previously fat, has now become heavier, leaner and definitely more muscled. I've rarely seen a domestic cat, in such good condition, that you can see their muscle tone through their fur, but this is now the case with my Egyptian Mau. I believe in keeping my cats fit and healthy and I believe that raw meat IS the best way of achieving this. I do not believe animals should be lethargic/fat/spoiled. They should be strong, fit and disciplined.
In saying all of the above, cats can live to 20 years of age, eating Whiskas and all the cheap supermarket food. You just have to decide how far you want to go.
You want the best - buy raw meat (with Taurine).