I sat down and watched the latest and weakest of the REC films the other night. Although this fourth entry is pretty good and wisely continues the story of the female lead of the first two movies it doesn't have the energy or thrills of those earlier movies. Much criticism was leveled at the REC 3 for tone shifting into some bloody comedy during its second half but I felt that film's story was well crafted enough to make the often odious mixture work. Perhaps concerned about the complaints of those that dislike their horror chocolate mixed with their comedy peanut butter, the newest film moves away from any hint of comedy (even when a crazed monkey is attacking) and remains as grim and serious as the first two.
REC 4's story is quieter, slower and less involving than the earlier three movies so I have to say its the least of the series so far. That's not to say I disliked it, but it left much to be desired even with an interesting twist on the movement of the central 'infection' from host to host. If you're a fan of the other REC movies its worth a watch but go in with lowered expectations for maximum enjoyment.
I'm a huge fan of director Jaume Balagueró's other movies and have been impressed with nearly every move he has made in the horror genre. Over the past fifteen years he has emerged as possibly the best of the current crop of Spanish Horror filmmakers and if you have yet to see his other work - THE NAMELESS, DARKNESS, FRAGILE, etc - I recommend checking them out for some great creepy horror tales.