We have 5 dogs (2 full bred Cockers and 3 rescue dogs of mixed breed) and switched them from Nutro Ultra to Evo. Did the transition over 3 weeks without any problems....no gas, no loose stools, etc.
We feed them less per day and keep them on the low end of the recommended amount for their weight. There has been no weight gain and the cocker with allergies (chronic ear yeast infections and biting his itchy feet) has done very well. My only recommendation, especially if switching from Iams, Science Diet or a grocery store food, is to make the switch gradually over 3-4 weeks.
This food is worth the extra cost.