Some of the brands that you see regularly sold in department stores are not necessarily the best quality, just a well-known brand. There are some niche brands that provide great fits.
I personally like Addicted mens underwear which is a brand from Barcelona. But then I like colourful underwear that is very fitted and their underwear is really bold and fitted.
The Andrew Christian brand is probably the best for underwear technology so they have something that will fit everyone great. For example, the have a collection called 'Almost Naked' where the cut of the underwear at the front creates and enlarged pouch that allows you to hang free, feeling like you're not wearing any underwear. This extra space provides more comfort but also reduces sweating, cinching etc. They also have collections that can boost your front measurements, help give you a bubble butt or slim the appearance of your waistline. But in terms of the best comfort, the Almost Naked collection is very popular and it is technology which creates a 'natural' fit.