The guys at Cajun Gun Works are great guys to work with... no doubt. They are really new to the optic milling game, though. Not saying they wouldn't do a good job or anything like that - it is just that, for my guns, I wanted someone who had done this a LOT to do the work. ;-)
Mark @ L&M would give you a great turnkey experience. The key IMO is that Mark
really knows his stuff and has been doing this as long or longer than
anyone. He was very patient with all of my pre-sales questions so you might consider emailing him (mark@landmprecisiongunworks.com) and see how that goes before making up your mind.
To be clear, I'm not trying to push you in a specific direction or anything. It was a nailbiter for me when I was deciding on who and what for my first MRDS build and, honestly, I couldn't be happier with the work and the whole experience I had with L&M. I just wanted to make sure you were aware of Mark's work before you made up your mind.
FWIW I mentioned Primary Machine simply because they are highly regarded by those on the CZfirearms forums who have had them do work... I don't have firsthand experience with their millwork, though. All of my guns have gone to Mark.
ETA: with a good shop, you only need specify what kind of BUIS you want (all black, fiber, tritum) and they take care of the rest... I went with a plain black rear and a custom fiber front on my P-07s.