The main, Lady Sif centric plot of "Who You Really Are" is a lot more procedural than recent episodes of Agents of SHIELD have been, but that isn't necessarily a bad thing. It's used to give us various information about the Inhumans that will no doubt be cropping up in a greater role shortly, and it's an interesting story in it's own right that contains links to the larger Marvel Cinematic Universe, has some funny moments with the amnesiac Lady Sif and ends with a pretty cool finale that sees the super being that Lady Sif was fighting tear his way through the best fighters in SHIELD.
If you weren't convinced that Agents of SHIELD was building towards the beginning of Captain America: Civil War before, then you should be now. The potential for a serious, moral divide amongst the team on the topic of those with powers is stronger than it has ever been, and the reactions on both sides are believable and consistent with their characters, particularly that of Simmons, who seems to have adopted a "shoot first, ask questions" later mindset. Admittedly, the argument is a little one sided at the moment with only Fitz and Skye against basically everyone else, but the seeds are there for this to really cause a large schism in the team, one that could easily have a huge impact on the rest of the Marvel Cinematic Universe.
Additionally, it looks like Bobbi and Mac's secret may soon be out in open after "Who You Really Are" pushes this particular plot line forward in a sudden and dramatic fashion thanks to Hunter's inability to let a matter lie. We still don't know who they are working for or what their goals are, but it's about time that this story progressed and I'm looking forward to seeing where the show takes it, which will hopefully be in a direction that furthers any divide that may be growing in the team.
On the whole, "Who You Really Are" makes for a memorable episode of Agents of SHIELD, and not just for it's guest appearance, but for instead ensuring that some of the plot threads that could have easily been dragged out for a while were instead dealt with and progressed. It's a better episode than "Yes Men", and a sign for anyone that needed it that the continuing increase in quality of the show won't be slowing down any time soon.