What are your main different card choices
How much damage will Doctor Doom and his corrupt cabal cause
This card provides immediate value on entry, which does raise its potential massively
It demands careful life management, but if you build around it properly, Necropotence does what black does best: convert risk into control
If you have a multiple-attacks-per-turn focus, this might be something you want to experiment with, but otherwise you probably want to keep this one in the binder
Its also what makes Commander interesting for a whole swath of players, players who see 120 life as a welcome challenge, who see keeping a board intact as a challenge, and who love to surprise opponents with a cheeky extra combat spell