The topic of which types of substrates that is best choice for bearded dragoon is widely debated in the reptile community. Many pet owners have the experiences on different types of substrate used for their bearded dragon and they would insist that the substrate is the best.
One of the biggest issues in selecting the substrate is the fear of impaction that may happen to the bearded dragons. If you are worry about the reptile impaction, then you should avoid using the substrate such as sand.
From my personal experiences of using substrates, I would say that there are advantages and disadvantage between the substrates. There is no best choice. You may need to try it out in the short term and decide a permanent solution for your bearded dragon.
There are many substrate choices in the reptile market today. Please be careful that not all the substrates are suitable for bearded dragon. Only the ones made for desert dwelling reptile are good for pet dragons. Do not use moss, wood shavings or bark substrate for your pet dragons. It may harm them.
There are many opinions on this topic. The best way to find your “best substrate” is to experience it yourself. Observe how well is your bearded dragon living with it. Once you found out the “best substrate”, it would be the best substrate choice.