Eh, I think you are right to contemplate switching. To answer your question, I too fed Roayal Canin Kitten to begin with, as that's what my breeder feeds her kittens, so I did it for continuity sake, but then I switched off of that a month in or so and began researching food like mad. Keep in mind that breeders have a lot of mouths to feed, plus Royal Canin will "partner" with breeders and vets, so they have extra incentive to feed Royal Canin, and you really should be able to do better. Plus with the age of your kittens, it's time to switch from the kitten formula to an adult formula.
If you were in the States I could list a dozen brands that I think are better (but Royal Canin is far from the worst, it's middle-of-the-road imo), but the best I can do is point you at some articles to give you some criteria for selecting some better food.
Keep in mind that statistics and all that are revealing and helpful, but your cats get a vote too! And it never pays to feed a cat a food that they don't really like. So that needs to be a big part of the equation. Also, especially when selecting canned food, your eyes and nose will often give you a lot of info about the quality of the food (in addition to looking at the ingredients). When something looks and smells like something you might consider eating, chances are they used some pretty good ingredients, and when something looks and smells really vile, chances are it is!
http://www.catinfo.org/?link=cannedfoodshttp://www.littlebigcat.com/nutrition/s ... -pet-food/