Yeah I think I saw @Spex post about them here first a few years ago. I didn't care for their selection back then, but they've improved a lot since. Much of their selection is also quite seasonal.I recieved my first 4 Spier and Mackey slim fit shirts 2 weeks ago. Very well made, substantial material, and the best fit I have ever gotten. I'm a 15.5/33 am 5' 9 1/2" and weigh 158lbs. They could be bespoke by how they fit. And what a great hand, thick buttons, and perfect bell shaped button down collar. I think they are 3 1/4or 3 1/2".
I have 2 of their wool trousers, and find them second only to my Hertling which cost almost twice as much.
I'm a convert.