Well, my three cats ate Royal Canin Prescription Weigh Control high protein 38 dry for years.  They seemed healthy enough on it.  And when I compared to other dry foods it seemed to be the one with the lowest calories coming in at 235 kcal/cup.  But two of them were steadily gaining weight over the years and reducing the amount being fed only made for grumpy cats.  So, with the recalls I started reading about feline nutrition and moved these two cats to all canned non-prescription cat food instead. 

The third cat, with IBD, never needed this food but ate it because his brothers did.  I've been working to move him off this food but haven't done it completely yet.  Got to be so careful with IBD.......I just recently have been trying their IVD peas and duck/lamb/venison/etc canned cat foods for him.  He doesn't seem to like them at all.

I also tried their dry prescription diabetic food for a short while for one of my cats last winter.  We were trying to see if the higher protein forumula would help with weight loss.  Around the same time he developed some tummy problems.  At the time we thought it might have been related to some dental work a month or so prior, but in hindsite I actually think it was the new food.  My IBD cat got just a few bites of this from his brothers bowl and got sick from it.

I am in Wisconsin

Two of my cats were prescribed S/O as they had developed struvite and oxalate crystals.  They loved the canned, as well as the dry food.  They are healthy now once again and I was able to take them off the prescription food.

I feed my cats a variety.  One of the products I used to feed them was IVD/Royal Canin prescription diets, canned--the venison, rabbit, and duck.  One cat often had loose stools but I don't know if it was from this or the other foods.  He seems better now that we've totally switched to other foods.  They were on this for several years.

I'm in Maryland.