Welcome to Smogon! Take a moment to read the Introduction to Smogon for a run-down on everything Smogon, and make sure you take some time to read the global rules.
This is a question about a PU Analysis, not a suggestion. If I'm supposed to ask this somewhere else, please let me know.
I was reading appletun's analysis, when on it's tank set I saw it suggest no item. Why is this? I see no reason not to run leftovers.