I have watched 28 Days Later, I am not a great horror movie fan and found watching this, quite stressful, in a good way. I was on a number of occasions surprised by the director not going for the easy fright, or not going for it in the way I expected. I am too much of a horror wimp to give this 5 stars, but I think it is quite a good movie.
Also 28 days has an excellent cast each delivering their roles very well. Mr Ecclestone is in a very Ecclestonian role. Very like a more modern version of the Day of the Triffids series (1981).
**EDIT** Now watched 28 weeks and changed from 4 to 5 stars. Excellent cast again, younger actors were brilliant. Cant remember the name of the actor who plays dad, do not usually like him in anything, but I thought he did both parts of his role well in this. As mentioned I am a horror wimp, so was literally hiding behind my hands at times but the story and pacing carried me through.