Re: Medallion of Courage on SD.
I play Shadow Demon quite a bit, and always follow the Soul Catcher/Disruption build with a single point in poison, since poison just seem to make me play worse by confusing me.
MoC is indeed a great item for Shadow Demon, but I also very rarely buy it. The reason is simply I prefer an Urn rush on that hero. And with warding, chicken, boots, wand and not stealing too much farm, I probably wouldn't get MoC untill after the 20 minute mark. And since -armor is most powerful early on, it seems a little redundant at that point.
Tranquil Boots into Medallion seems very powerful, since your regeneration would be fixed so you can roam all you want, and all you have to worry on from now is bulk/utility. Probably wouldn't be enough mana regeneration for a poison build though. It still seems pretty solid.
If you're giving SD some farm, I would much rather rush a Guinsoo than MoC, but I tend to play him with minimum farming and lots of ganking.