The first launch of the SLS has slipped again [spaceflightnow.com]:
NASA has decided it must delay the maiden flight of its Space Launch System rocket, presently scheduled for November 2018, until at least early 2019. This decision was widely expected due to several problems with the rocket, Orion spacecraft, and ground launch systems. The delay was confirmed in a letter from a NASA official released Thursday by the US Government Accountability Office.
The Falcon Heavy will be able to deliver payloads that are similar to what SLS Block 1 can carry [spaceflightnow.com]:
In its maiden flight configuration, named Block 1, the heavy-lifter will be able to haul up to 77 tons (70 metric tons) of cargo to low Earth orbit, more than double the capacity of the most powerful launcher flying today — United Launch Alliance's Delta 4-Heavy. The Block 1 version of SLS will fly with an upper stage propelled by an Aerojet Rocketdyne RL10 engine, based on the Delta 4's second stage.
SpaceX's Falcon Heavy rocket, scheduled to make its first flight later this year, will come in just shy of the SLS Block 1's capacity if the commercial space company gave up recovering its booster stages.
NASA plans to introduce a bigger four-engine second stage on the EM-2 launch, a configuration of the SLS named Block 1B.
GAO report [gao.gov].