The difference between the Gen 2 and Gen 3 is the installation.
The Gen 3 barrel nut does not require timing and has our new pattented torque plate which prevents over tightening for people who can not read a torque wrench.
As for comparison to DD, they make a great product from my limited experience.
I have no idea the differences because I use MI on my guns.
I would bet ours is less heavy, but your asking about quad rails so you probably don’t care about weight.
I would guess we have more QDs, but that’s only important if you sling up.
They are both made in the USA.
Ours is less expensive.
Take your pick.