When it comes to incubating just like pretty much everything else it comes down to what work best for you and what you prefer.
I have been incubating eggs with the substrateless method for 7 years and never had any issue, I like this method, it's easy and foolproof.
I use 7 quarts tubs, 6 cups of vermiculite, 3 cups of water and incubate at 89 degrees.
The substrate is not in contact with the eggs, the eggs never get wet and never dry out.
Maternal incubation can be done successfully however your husbandry must be perfect to start with, conditions are often a lot simpler to provide in a very controlled environment such as an incubator.
My goal is to put all my chances on my side which is why I use an incubator.
In the end it's all about what YOU like best.