Boring as hell
This was an interesting premise - to have two movie tell the same story from two different perspectives: Her and Him, and then the producer insisted on a third composite: Them - but the story of the erosion of a marriage after a tragic incident couldn't support the finite examination, it bleed out into a tedious demise. Jessica Chastain and James MacAvoy (with an American accent) gave us well articulated characters, as you would expect from them, but the pace of the story telling and its excruciating slow resolution is challenged to hold its audience once, let alone three times. I watched the three movies in this order: Her to which I gave a 7 (good) out of 10, Him a 6 (fair) out of 10 - and finally, Them (only under a self imposed obligation to give them all a fair critique), which I gave a 5 (meh) out of 10.
If you have watched Him and Her versions forget about this one. Nothing new and scenes are badly put together. Too many sudden cuts, and changes of scenes and moods, no explanations. If you wonder which scenes are used that are in both movies, here it goes, class- from Him, car- Him, apartment- Her, ending- Him.
Even if you haven't watched first two, skip Them, you really don't need it, and instead watch Him and then Her. I think it would feel wrong to watch first Her and then Him.
And yes, as others here have said, this version is boring, but I have enjoyed Him + Her.
I couldn't finish it, I fell asleep