they’re no better than chain store shirts for similiar prices.
I just got some non-iron ones – they certainly feel like everyday shirts rather than the lush thick twill I got from Lewins for not much more. The sewing etc seems good, will let you know in a year or two how they hold up.
However the big advantage imo is fit and choice. You get to choose collar and fit AND sleeve length; you also get to choose not only lots of colours and patterns but also weave types. I was able to choose slightly less smart shirts which will work with either a suit or casual trousers for Scandinavian/German use.
That in itself is worth a lot, but it only costs you £20. Win.