I find it interesting how everyone likes or dislikes different Black Mirror episodes in different proportions. A great deal of your opinion of an episode has to do with personal experiences and philosophies, a successful echo of the use of "Mirror" in the title.
Men Against Fire was really testing my patience for the first thirty minutes, the first time I had experienced agitation with an episode of the series. We have already seen so many of these themes with "History of You" and "Playtest" that the main character's fascination with the technology around him was belaboring any point that needed to be made. However, the episode did a fantastic job of bringing it all together and causing the viewer to re-examine previous events, a la "Shut Up and Dance". With a clever turn of events, all of the reasoning was explained to my satisfaction. Another solid theme explored by Season 3.