I don't think there is a single thing wrong with a 700 action, and I do agree that truing them is typically not needed. That being said, the more 700s I've built, the more things I find I want to change about them, to the point a custom just makes more sense....for me.
The Mack Bros action is very intriguing, but I've yet to see one in the flesh. I think the CVA Cascade could could a very interesting action to build off of, but I am unsure of bottom metal compatibility.
