My daughter (2000) went to Curveballerguy for about a year for weekly lessons and ultimately played on his travel ball team and enjoyed every minute. It was a long drive, almost two hours each way every week and worth every minute.
He was always honest, was never harsh, mean or rude. He was encouraging and positive but didn't cut slack if she didn't do her spins or other drills between lessons and he knows enough to know when she did or didn't. He told her when she was good and told her when she wasn't. When she wasn't good he told her why and what to do to correct or improve. We were fortunate, she did improve and ultimately got a D2 scholarship offer that in large part came from his tutoring..
I sat on the bucket, kept my mouth shut unless I didn't understand something and let him do his job. I only asked questions so I could work with her between lessons and never once tried to take over or coach her and we got along great. I learned a lot about pitching, pitches and even coaching and I've been a coach a long time. I think a lot has to do with what mindset you go in with. We went in looking to get her some good instruction and help her improve and we got what we paid for and more.
If you want your daughter to learn to throw a true rise ball and not a fastball that has an upward trajectory and to throw a curve that really has good spin and a good break, then this is the place to go. Be ready for honesty though.