Fun addition to your COH2 Singleplayer experience. Do note, this DLC is highly unsupported by the devs.

The multiplayer aspect along with the US army faction has changed (Units and their stats mainly). Many changes happened from 2014 until today, so the DLC is quite buggy but not unplayable. Some levels will be "Dark Souls-like"; some units will be unavailable, because the USF SP and USF MP factions share the same stats.

But either way, it's a fun experience to play it.