We are all so different...you will find that individual person's experience with a brand will usually be universal to that brand. How someone's body reacts to the chemicals in that brand is usually the cause
some of us need convexity or have allergic reactions to the adhesives.
I have tried all of the major brands and some of the lessor know and have my favorites but use the brand that works with my body. Personally, I use an Eakin Seal (and have for 10 years) with the Coloplast Extended Wear Wafer and a Velcro drainable pouch with filter (2 piece). I also use a Sure Seal over my wafer to protect my wafer from moisture.
I don't use adhesive remover or skin prep...I find that their residues can shorten wear time but will use Stomahesive Powder when needed. My wear time is anything from 3 days to 7 days and usually depends on the time of year and my activity level during that time!
I personally prefer a two piece system because a pouch NEVER lasts as long as the wafer
and I change my pouch regularly.