Quarantine isn't a bad movie by any means. It just felt like a Hollywood remake that gets so many things wrong. 1) The protagonist. The female reporter character is important. Angela (in Rec) kept it together and remained a reporter throughout the movie, no matter how afraid she was. In Quarantine, Angela falls apart immediately. Instead of the strong reporter that is coping with the situation (while showing signs of duress), the Angela in Quarantine doesn't come across as such and proceeds to screech and cry hysterically. This is just my personal tastes though. Some of my friends like Q's Angela more because they reasoned she was less experienced. In the end though, I felt that Angela (REC) was a heroic protagonist while Angela (Quarantine) felt like another victim.
2) Quarantine feels fake. The flashy slickness and faked lighting kills the realism that REC had. In REC, the camera work and lighting was mundane, which helped it feel like it really was a camera guy filming a local reporter in a shabby apartment building. Quarantine instead goes for scary movie ambiance, which isn't necessary.
3) REC never explains the cause of the whole zombie-ness. The movie hints at it near the end (the creepy room with the creature and all those newspaper clips alluding to some religious incidents). In Quarantine, one of the minor characters, with great insight, reveals to us that a mutant-super-rabies virus (or whatever) is the cause, which is less scary and interesting. The cause of a zombie outbreak is NOT SCARY, it's always the result. Keeping it secret allows the viewer to imagine the cause, which is far more interesting.
That's most of my complaints. I also think Quarantine was hurt because I recognized some of the actors from different films (Jennifer Carpenter from Emily Rose, Jay Hernandez, etc).
I hope I don't get it with subs.
Why's everyone think Super rabies is soo stupid? rabies leads to dimensia, violent tendancies, increased THIRST, elimination of pain, no self preservation. Its easily spread through saliva/blood. 
