I can say for sure, that Gregs Course is an amazing course. I payed for it and was glad I did. Last year he had a summer half off sale and that made me jump on it.
The great thing about it is once you pay for it you have Lifetime access to the course. For instance with the big changes this year the course changed to cover night flights and flying over people, remote ID. With the lifetime course access you can go back and watch the updates. He also will tell you if you are going back through for the Recurrent test what sections you need and what ones the skip.
He does a great job of trying to make some of the dry and boring stuff more exciting, but he warns you when it is coming so you can decide if it is time to take a break and come back or not. I finished the course with 1 day before my test scheduled and took that day off. Went in and missed 1 question. Sent my sheet to greg and got a free t-shirt.
I do not have any financial interest is Pilot Institute, I payed for the course and would have gladly paid full price in hind sight, and I do not like to spend a lot of money! Maybe I will watch theutute youtube course and do a comparison video between the 2.
Dave