I loved the first two series, well the first one especially before they all became much more aware of the cameras, but I haven't found this third series anywhere near as enjoyable. There aren't as many interesting personalities (at least they've not spent much time building them up) and some of the ones they have focussed on seem like they have some really tragic severe issues that need to be dealt with away from the cameras.
Conversely I've found the new coach to be a total arsehole, I've struggled to find any redeemable qualities in him. He seems really insecure in himself (how many times has he mentioned his beach house and collection of average cars?!) and his coaching ability (he seems to take any comments/suggestions as a personal slight and attempts to shut down and belittle the player or the coach that made them) on and is abusive to his players, and not in a shouty-but-ultimately-motivational-and-good-for-them way, but in a really personal antagonistic way that seems designed to destroy their confidence. At one point he was even having a massive go at some of his coaching staff in the middle of a game, after they suggested some alternative tactics. It was bonkers. The camera cut to the college dean during one of his outbursts and you could tell he was regretting the decision to bring him to the college.
Whereas although Buddy from S1-2 was loud and aggressive towards his players it still seemed to be within the boundaries of what you'd expect from a coach and focused around the game, rather than personal insults.
His motivational speaking is really poor too, and he tends to contradict himself. There was one episode where he was trying to instill in them the importance of at least turning up to classes, sitting at the front and listening, handing in homework just to ensure they passed the course, and then right at the end went off on another boastful rant about how he was a total baller and managed to blag his way through college without really trying anyway. It was bizarre.
I also felt really sorry for the QB coach, when he gave a tour of his living quarters, which looked less welcoming than a prison cell, and then casually mentioned that he wasn't even getting paid. Tragic.
Obviously I'm going to watch every episode though, and after watching almost 3 series of this I've still got pretty much NO IDEA how American Football works!
For your spoiler, the S4 ep is just a catch-up with a lot of the players from S1-2, don't know why they bothered calling it series 4 really, it makes more sense to watch it before S3, you can watch it any time.