I have both and I prefer the M10A. They both have good build quality and durability, but I like the lower low on the M10A and the simple ring mode changing. Simple and foolproof. I like my LD10 as well, but the "bezel tight, bezel loose, click, click" mode changing isn't as nice.
I'll put it this way - I just got a titanium Sunwayman V10R with AA extender. I like my M10A enough to spend the $$$ and buy the fancier upgraded model of it! My Fenix lives in my truck, my Sunwaymans live in my pockets.