The answer, I think, depends on which is more intuitive to you. Mils are 1/1000 of a radian, while minutes are 1/60th of a degree. Which is easier for you? If you want to use the marks to estimate range, and you are comfortable with the metric system, then I'd say the Mil-quad would be better. Just start thinking of your target distances in meters, not yards.
In looking at the pictures of the two, my own impression is that the MOA quad is a bit too busy. That is, the spacing of the fine lines being only 1/2 MOA is a bit too closely spaced. I have the SS16x with standard mildots and would rather have the half marks on it.
I will say (though these are two different brands and price points) the 10X 1/2 mildot Hawke is a quite a bit brighter than the 16X SS. I also think that the Hawke 1/2 mildot reticle would be a bit nicer to use as the half marks are little butterflies.
For the most part, I do not find that the additional magnification of the 16 X helps too much over the 10X with these two scopes.
I will say that the SS 20X is quite a bit dimmer than the 16X, and has a smaller exit pupil. These factors make it a bit harder to use.
There is one other thing that I found with the two SWFA SS scopes that I have. If you have droop and your reticle is not close to optically centered when sighted in, the focusing will change the reticle position relative to the target image. This became apparent when my previous trajectory cheat cards with the Hawke scope, did not correspond to what that same rifle and pellets did with the SS scopes. It seemed like I had a much flatter trajectory than possible. Once I made new cheat cards, all was well.