Ok so I like the series. I started watching it because I love The Challenge and there are players that got their start on BB. So I watched a few of the older, better rated seasons and enjoyed the addition of twists along the way to make the game more interesting. Then I jumped to the newer ones that had Challenge players in them. I'm on season 18 and EVERYBODY IS YELLING IN THEIR CONFESSIONAL/DIARY ROOM!!! It's super annoying. Also? The big difference is that usually the players either have never played BB before (unless it's all-stars, and sometimes they sprinkle in returning players), and people are so bad at lying/scheming it's often cringe-worthy. Again, watch The Challenge, as it has return cast members pretty much every season so they've actually learned how to politic and play people. With the majority of cast members being newbies, with them comes lots of "look at me, I'm on tv" as opposed to returning players who don't seem as aware of the cameras and don't seem to be playing a character as much.
P.S. If you like this show and have never watched The Challenge, watch it from like season 19 (or earlier if you have time), on forward. It's the same idea as far as politics but the challenges are less like carnival games (I'm sorry but it's true) so there's more focus on physical competition. Much more entertaining, but helpful to know the players from earlier seasons so you can follow the beefs/drama/struggles.