All I know is I don't want to go back to the crap soap I was buying and using for years before I started traveling.
I don't know soap brands too well... just get to know which ones I like from staying at hotels.
I looked at online prices for some of my favorite hotel ones: Le Labo, Shanghai Tang, Thann, Thatworks, L'Occitane.
I couldn't believe how pricey those were. Actually couldn't even find Shanghai Tang soaps available online anywhere, except at Ebay type sites.