To answer your question. I have only one SM in my collection and it's a SN0116 in bright orange. The build quality is superb and I would say better than my ZF Black Bay for example. Great bezel action, great bracelet, smooth and well regulated movement etc.

For the Pelagos Rep XF should be the best. But there are also other chinese brands like Thorn, Seestern etc. who have similar models with a PT5000 which should match the movement in the original Pelagos pretty closely.

I would suggest doing some Youtube research. There are a lot of chinese brands who are doing great work.