I got an Inzer Lever 13mm like 6 years ago and have never looked back. I guy I lift with sometimes got a 10mm last year and I tried it on once. It was pretty much the same feel until I hit max squat and then I didn't feel as much support IMO. Outside of max lifts though I didn't really notice a difference in terms of fit and feel or if anything the 10mm was maybe more comfortable. But I wear a belt for support on max lifts not comfort so 13mm for me it is