I am a doomer, and I like community wads as much as I like Plutonia. I came up with the idea of scaling IWADs and community WADs by difficulty in 10 levels. From 0 to 9.   0: Not an accomplishment to complete, even on Nightmare difficulty, Nightmare.
  1: Playing this is pretty easy, even on UV-fast.   2: A little bit harder, but still pretty easy.   3: Medium, usually pretty fun.   4: A bit harder, but it’s not the hardest.   5: Kinda hard, but still fun.
  THE ULTRA-FILTER Doomer, if you have completed WADS which rank 5, then you are ready for higher ranked WADS   6: Pretty hard, a bit of skill is required.   7: Very hard, you might want to practice on a Level 4-6 WAD before playing this WAD.   8: VERY hard, skill is required.   9: These WADs are the greatest challenge, only the best Doomers can finish these WADs. If you manage to complete one, you are truly a supreme Doomer.
 
Here is a scale, which uses the Iceberg template.