First realize that adult incontinence products, as the industry calls them, since adults cant bring them selves to call them diapers, are broken up into two categories: diapers(fitted briefs, taped briefs) and pull ups(undergarments).
Diapers are generally reserved for more heavy incontinence as its harder to hide a diaper underneath clothing both due to bulk and noise and they tend to be more expensive. they are of course designed to hold more so they are bulky. Pull ups on the other hand are designed to be less bulky and more discreet. generally not good for night time incontinence(bed wetting-enuresis) and overall best for day time use when heavy incontinence isnt an issue. Bowel incontinence essentially makes your choice for you as pull ups arent designed to hold fecal matter well.
something else to realize is that you have to levels of quality in the adult diaper/pull up market. you have the cheap store and off brands. not only are they cheap but they are designed extremely poorly and any upfront savings is lost by having to change alot more. then you have the high end brands. the ones you pay extra for and can only buy online.
Brands like:
dry 24/7
molicare
abena abriform
Of course there are more but I have tried all three of these brands and swear by them. They are comfortable. Certainly on the thick side but for me and my active lifestyle, i really dont worry about people noticing. I want to be protected and that is what matters. If you want a diaper that will offer superior protection and allow you to be active for long periods of time with out stopping to change then choose one of the three or another premium brand.