At the moment an Roll20 user and trying to migrate to Astral.
Astral has a lot of very good features, but one thing that is really pushing me away is that there is no compendium.
Compendium is one of the features that I most use while preparing characters/combats. Since you can easily drag and drop spells and monsters into your campaign.
To prepare a campaign with several mages, would be a mass time waste to create each spell.
To setup quick fights with monsters, another mass time waste.
Astral is going to for a really nice path with a lot of good features, but without compendium to backup the systems, i think i will not be able to migrate from Roll20, yet.