How did your child do with whole milk after being on Nutramigen?

When my son was born we tried enfamil and he would throw up his entire bottle. We went through 2 other formulas so his pediatrician recommended nutramigen and it worked really well. He was diagnosed with reflux but I’m not sure if he has a milk intolerance. How did you guys transition to whole milk? How do I know if he has a milk intolerance? I’m obviously going to be discussing this with his pediatrician but I just want to be prepared and I wanted to hear some experiences beforehand as well.