Not sure what state you're in, but my kids used to have CHIP (not Medicaid) in PA. It was great. They were on it for 3 years and we never had any problems with CHIP. My son has some medical issues. He had lots of tests and medications, and for the most part, it all went smoothly.
I had him in the ER once, and the family next to us was there because their child had pink eye. I remember thinking, "who brings their child to the ER for pink eye? Why not bring them to their PCP?" Well, when the ACA first started, Aetna was reorganizing their network, and there was a short length of time where aside from your PCP, Aetna was only allowing CHIP patients to see Medicaid doctors. My daughter broke her arm during this time. I took her to the pediatrician who sent us for an X-ray at the hospital and then called to tell us it was fractured and that we would need to take her to an orthopedist. I called Aetna to get a list of Medicaid orthopedists, and none would see her (not taking new patients, didn't treat children, only did surgical cases, etc). I kept calling Aetna back for more names and was calling doctors up to 3 hours away who wouldn't see her. I was sitting in the X-ray waiting room crying with my daughter sitting next to me with her poor broken arm. The receptionist then got a hospital administrator who called Aetna on my behalf and they still couldn't help me. There was only one orthopedic group I could find, however, they only saw patients who were referred to them by the ER at another hospital. I asked Aetna if they would pay for this unnecessary ER visit because she already had the X-ray and diagnosis. She just needed a cast. Aetna wouldn't say one way or another if they would pay it. I took her to this other ER. They had to take another set of X-rays b/c their computer program couldn't view the CD from the other hospital. They referred her to the orthopedic group, who couldn't see her for 3 days and then had to take another set of X-rays b/c 3 day old X-rays weren't sufficient. She got the cast. Aetna paid everything 100%. And I finally understood why a family brought their child to the ER for pink eye. They were probably on Medicaid and couldn't find a doctor who was willing to see their child.
I wouldn't hesitate to have my child on CHIP, but would do whatever I could to avoid Medicaid.
Why not try the CHIP? You could always buy him other coverage if it doesn't work out.