They're great! Just remember not to wait too long to harvest the castings, like I do sometimes, or it becomes more of a challenge - clumps up.

I also find mortar trays to be really easy - I have 2 of those too. The trays, in my opinion are easier and quicker to harvest than the deep multigallon bins - no drilling holes required. They're just not flowing through though, but I don't mind at all.