Actually the biggest tell is the edge of the sapphire glass. The gen and some ultimate version have frosty edges that you can't see the 'Swiss made' straight without tilting the angle. The cheaper rep edges are see-through. The process of assembling both sapphires is different too. Cheaper rep is top down, and the gen or ultimate rep is bottom up.
After having not less than 15 Luminer Marina from Base to Automatic to Chrono to Submersible, I finally got my first Radiomir. The reason why I have never gotten a Radiomir was the size concern. 45mm was a psychological barrier that I finally crossed, and I am very happy with this handsome piece. I have taken a few pictures to share with you. Enjoy!