My 2017 did a recent Top 96 event.
A couple of the schools that my son is particularly interested in were going to be in attendance, so it seemed to be a good event to attend.
He emailed the coaches to let them know that he would be there and was looking forward to getting a chance to meet them. The listed coaches were there, and he actually did get to speak with them for a few minutes during the course of the event.
I don't know if it will work out the same for everyone, but this was how the one on one worked out for my kid...
His evaluator was a coach from a local NAIA school. He introduced himself to my son on day one, and saw him go through the PFP work. The next day my son pitched a couple of innings in a game, and didn't really look all that good.
After my son was done, the coach went and got him from the dugout and took him and a catcher out the bullpen. They were probably out there for about 20 minutes.
Once they were done, my son and the coach came over and we talked for about 10 minutes. He correctly diagnosed that my son was in the middle of some mechanical changes and made a couple of suggestions of things he thought should be worked on.
After discussing my son's performance, we talked about my son's future goals regarding baseball and education. The coach said he was impressed with my son's mound presence and willingness to listen to instruction. He asked my son to come out to see him at the campus, and would like him to work with team at a couple of practices. Son will be taking him up on the offer.
I can't say everyone will have a positive experience, because I think it really depends on the coach you get assigned to.
I will say that a school that was on my son's list got scratched off because of the coach that was there. My son said the guy was a complete a-hole to the players, and wasn't much better to the other coaches.