The different shapes do create different sensations. I purchased the All on Black and the Lucky 13 after being so satisfied with the High Roller. The vibrator wheel function and intensity are the same. The Lucky 13 has a curved tip, so it's going to hit that special place. The All on Black is hugemungous, that's the toy I use once I'm loosened up from all my other vibrators. Just go with whichever one looks the best! I chose based on my sensitivities; for example, even the little bumps on the Lucky 13 irritate me sometimes, so I went with vibrators that have smoother contour.