Thanks to Akihabaru for the idea of making a rating guide of sorts. I mostly rate based on if I think it was a 'good' watch/read. A 'good' watch/read for me is something that has one or more of the following qualities: enjoyable, interesting premise especially if well executed, well executed themes, interesting power system that works well, interesting characters, great worldbuilding, and it can easily make you sad through the loss of a character (by getting you attached to that character). Shown by these is that my ratings are clearly heavily opinion based.
2 or lower - It wasn't a good watch/read. The show itself was pretty bad. Gets progressvely worse as you go down.
2.5 to 3.5 - It was alright. It was a pretty good watch but some parts weren't too great.
4 to 4.5 - Was a really good watch/read. Would recommned. Only falls short in a small number of areas.
5 - An incredibly good watch/read. A masterpiece.