I had 3000 hours into R20 Pro then switched to gaming exclusively on Foundry. I run 5e, OSE, Alien, Vaesen, Call of Cthulhu, Mothership, and Astonishing Swordsmen & Sorcerers of Hyperborea (ASSH). Of all these rulesets, only ASSH did not have support in Foundry which required that I hack...