I am a 4.5 player and I tried out the 16x18 and was amazed with how it hit on pretty much all types of shots. I think I'm going to make the switch... I'm coming off the head speed 18x20 (non IG). Again I am around the 4.5 level. I can put it away on the forehand side and hit with a good deal of topspin. My backhand isn't a weapon but I hit a consistent and penetrating slice (something I heard the 16x18 excels at). My serve is also solid.. I hit with a funky side spin action. I feel like I'm already sold on the 16x18 but im saying that without trying the 18x20. for those of you who have tried both, would it be wise to waste more time and money on trying the 18x20?