I definitely have opinions on material, size and thickness. I look for picks that “do it all”. I have used celluloid, nylon, Ultex, real tortoise shell, wood, bone, and fleetingly, metal. I have grown to prefer Ultex, with nylon as a first runner up. They sound, and feel perfect for me. I play more rhythm than most of my peers. I need a lightweight, fairly thick, and non-slippery surface. The Dunlop Ultex Jazz III (large) is my new go to. I used Dunlop EJs for years, but I started dropping them. Dern arthritis in my right thumb. I dislike celluloid (“click-ey”& bright), metal (chirps), wood (dull), bone (feels weird), and stone (chirps, and chips).