I will agree with JavaGuru that milk isolate is a good choice as long as it is not around your workouts and you do not have milk hypersensitivity. I will agree with lifterforlife that PDCAAS doesn't mean much at the end of the day if your eating well over your protein requirements , which most everyone is. Also digestibility can be handled with betaine hydrochloride and digestive enzymes, probiotics, etc
I like the red meat for several reason
1. raise test levels
2. vitamins and minerals
3. most folks tolerate red meat
4. variation for a balance diet
Repetitively eating the same thing over and over is simply not a good idea