I'm a filthy casual.
Here's the system I rate on. I recommend anything 8-10.
5 - Pure masterpiece
4.5 - Very memorable and extremely well done
4 - Very enjoyable and well done
3.5 - Great, I liked it
3 - Above average and likeable
2.5 - Average, okay anime.
2 - Bit below average
1.5 - Pretty bad
1 - Waste of time
0.5 - Not a single redeeming quality