I haven't heard the Gibbon 88 but I own the Gibbon 9 (no longer made), and I can't say enough good things about them. They are fantastic with tubes or solid state. In one room, I had them only about 18 inches from the back wall and there was no problem, and I am usually very sensitive to room boundary interactions. My understanding is the 88s are designed to work well in smaller rooms. Based on reviews, I would suspect the PMCs might be more of the "fast and detailed" speakers, but I went from the very fast and detailed Verity Parsifals to the Devores and don't miss a thing.