As of right now my sideboard has been largely shifted towards a split in dealing with Combo and Control. Creature heavy decks and decks packing burn spells aren't too troublesome because we already have an unusual amount of life-gain for a Mono-Black deck in Jitte and Nighthawk. Removal obviously helps against creatures, so I've been adjusting and evaluating my board taking all things into consideration.
As of right now, my board looks like this:
//Sideboard
[3x]
Dystopia
[3x]
Sadistic Sacrament
[3x]
Thorn of Amethyst
[3x]
Gate to Phyrexia
[3x]
Faerie Macabre
I'm really focused on trying to shut down slower combo with Sacrament and punishing faster combo with Thorn (with a solid discard package). Gate to Phyrexia has been effective against artifact-heavy decks, which could be a problem post-Scars. It's still in flux, but this is working great for me so far.