I have a tie and a MTM shirt from them. I have about 5 shirts from Luxire.
Quality wise they're the same I'd say, the stitching and craftsmanship of both shirts are excellent quality. However the main advantage for me is that Spier&Mackay is local so when I got my first shirt that was MTM, Rick pointed out some things that I would have overlooked such as tie space and collar band height, fusing vs non fusing etc.
I got their default spread collar with my shirt and for a "fused" collar it's the most comfortable collar I have. I have some other crappy MTM shirts with a fused collar and Spier&Mackay is miles above them. In my picture I"m not wear collar stays at all and the collar just sits flush and doesn't move
Going forward I'd like to see more basic fabrics for MTM and better selection of ties and actual fit pics kinda like how proper cloth does it with their collars.
However MTM is about 30% of his business (correct me if I'm wrong).
Thanks. Great to know. And what about the quality of the fabric?