The MBUS will work just fine. It is a quality product but it is made of plastic and I would hesitate to use it for a real tactical gun. But for a non-duty weapon, it is great. Keep in mind that since it folds, it could break at that point. If you are not using it, it is probably best to fold it down. Makes storing and transporting it a little easier that way as well.
The MOE is a good grip. I prefer the MIAD, but personal preferences are why we build or own guns. The MOE fills the hand well enough and has a decent gripping surface while not being too agressive.
I have built a couple dozen guns over the years and modified as many for guys.