I stuck with Toolbox for a long time because it was default, but then I wanted to be able to easily recreate my *boxes with the same set of packages when e.g. they broke for some reason, or because the distro they were built on released a new major version. Distrobox supports that with its assemble command, so I switched. Otherwise it's not too different really, for a casual user like me, and if I hadn't needed assemble, Toolbox would've been just fine.
(Except that I keep forgetting whether Toolbox or Toolbx is the correct spelling now.)