This is a hard call to make because both types have merits and demerits. The core factor when it comes to this is to consider your working capabilities and the type of weather you hope to face.
Freestanding designs are pretty easy to mount and take down. They will also easily be mounted anywhere, including on rocks where drilling holes is impossible but may not be stable enough for strong winds.
On the other hand, supported shelters have the ability to stand firm against harsh weather but will take you some time to properly set up. The choice is all yours.