The problem with rating services is: rating services. Witness how many prospects suddenly jump by one or even two stars once they are offered by major players in power conferences. Guess what, the prospect didn't suddenly get better, the rating services just happened to recognize that the college coaches and evaluators just may know a thing or two. Butch has done OK recruiting, I trust him. Wow, long time since I have been able to say that about a UT coach.
First, he is a 4* on Rivals (see my post last night).
As to your question, in reality who really knows. I would note the VOLS currently have a former 5* receiver on the team. I do not star gaze. The relative value of any recruit, no matter the service star ratings, is in his ability to learn, to fit in and develop within the program. I have no empirical data but I suspect that the number of 3* that perform as a 5* and the number of 5* that perform as a 3* are not that much different