Really? I think it's pretty clear that the leather loop (all colors) is primarily intended for men, and the modern buckle is primarily intended for women — hence why the leather loop is only in 42mm and the modern buckle is only in 38mm, and why they each come in a different hue of otherwise redundant colors (each in a black, a brown, a blue, and "stone"/soft pink). I don't think any of the leather loops look feminine.
Of course, they're all pretty understated, so I wouldn't worry too much about it and just get what you want. (I'm surprised how many men are getting the Milanese loop, which to my eyes is very feminine.) I got the modern buckle, and I would have even if the leather loop were available in 38mm. The modern buckle just looks dressier. And after playing around with it in-store, I think I definitely made the right choice. The leather loop is fine if you want something adjustable and easy but it's not as soft; you can definitely feel the magnets.
and i guess i've known it all along / the truth is, you have to be soft to be strong