Ignoring varying subjective tastes in fashion, I think that it's better overall than what we got in the past two gens.
S/M and US/UM had a horribly lacking selection/variety of options, made worse by the fact that colours were split up between the versions. XY had a better selection than the Gen 7 games, but was spread too thinly across the game. The first boutique only sells hats, and obviously not all of the hats. The next shop you run into is the one in Lumiose City, but that has a barrier to entry and the stuff inside is very expensive, meaning it's not an option until later in the game. Though there was at least the hair salon, but two of the hairstyles are not initially available, nor is there a preview for what your hair will look like. It's not until the 2nd badge that you can even begin to try to make something different than the starting outfits, but it'll take more time still to have a lot of options available.
In SwSh, there's a clothing store in the first town, and one with a decent selection at that. Not long after you gain access to the hair salon and a 2nd boutique in Motostoke, giving you more customization options very early on. The remaining clothing stores (Hammerlocke, Circhester, and Wyndon) are all spaced out well enough (and don't specialize in certain kinds of clothing like in XY) so you don't have to wait ages for more stuff. There's also some new options like outerwear and gloves and such.
It's not perfect though. Some categories could use more options in general (shoes, dresses--but praise be the ones in Circhester), and there's some missteps like being forced to wear the uniform, even after you become Champion+not being able to wear the other uniforms for Gym Challenges, or having to wear a specific outfit when riding the bike (just slap a helmet and pads on over the character model, it can't be that hard). Then there's the continued insistence that Orange Is Not A Hair Colour. Have all the other natural hair colors, have all these non-natural ones, but no orange, same as last gen. Like does Game Freak have something against gingers or something??
But, since it's an improvement over the previous games, hopefully it means that we'll continue to see improvements and not regress in this department.