Notice that with the Eukanuba you get 2 sources of meat or meat products before you get to the corn/rice. That means there's at least twice as much meat or meat product in Euk than any other single ingredient
Notice also that the corn in EUK is ground corn as opposed to Corn Gluten Meal which is a corn waste product basically and has less nutritive value
Euk has 10% moisture compared to Pro Plan's 12%. What are you paying for, food or water?
EUK has chicken fat compared to Pro Plan's beef fat which isn't as digestable
Her stools are much better than they were on anything else and she looks like a million bucks. I know others that have had these same results. The only formulation (I haven't tried it) that comes close to EUK is Black Gold Ultimate Performance.
I have fed lots of stuff. I keep coming back to Euk PP for the working dogs. Quality wise to me it's the best. It isn't cheap, but I buy it at the PX and use their Retail Rewards, so it's not bad, and when I'm in Memphis, I can get some through a friend of mine who has the brown bag deal going.
Pro Plan Performance works great for some dogs - it didn't work for mine. I didn't like the high amount of grains in it for the price I was paying - just ask someone from another dog food company - the corn gluten meal counts as part of the protein count in that food. Again - it works great for some dogs, but it didn't work as well for mine.
I fed Arkat Enhance Professional Athlete - really, really liked it - stools weren't quite as good on it as on the Euk, but it did fine. If I could get it at a store nearby I might give it a longer try.
Have fed Eagle Power Pack and really liked it - but the store that carried it for me is owned by a guy who is a Senior VP at Nutro and they wouldn't keep it in stock and asked me why I just didn't feed Nutro....... they do manage to keep some Euk in stock and only ask me about every 3rd trip in if I'd just feed Nutro.
You have to find what works for your dog - there are lots of good foods out there, and no one food is right for every dog. I'm sold on Euk for this bunch. Even put my old guy on Euk Senior and have had great results with it.