My main diaper is Tykables Overnights, size L (formerly size 2). The fit is great. They rarely leak. (I've yet to find a diaper that never leaks.) And I really like the hook-and-loop fasteners. Since I only use diapers for wetting, having the option of removing my diaper and putting it back on is sometimes useful.
ABU Simples are my second-favorite diapers currently. ABU size L diapers fit me well, and I like some of the designs in their print diapers, but I like the fasteners for Tykables more. I like to keep some plain white diapers on hand. When I travel and think my bag might get searched, I prefer to pack diapers that aren't AB-themed.
It's been a few years since I tried diapers from any of the medical brands. Abena M4 used to be my favorite, but I gained a couple of inches in the waist, and they started leaking. Abena L4 is too big. I'm skeptical of any brand that comes in only two sizes.