Let me just say the film's are great, well the first is, the second is a it lackluster but you can go elsewhere for reviews of the film.
The quality of the Blu-Ray is terrible, the first film honestly looks like a VHS and worse than my DVD. The second film, 28 Weeks Later looks acceptable, but still not great.
If you're looking for a film that oozes Blu-Ray quality this simply isn't one of them. Maybe that's why the double pack is so cheap, the first film does not deserve to be on a Blu-Ray disc, it's VHS level quality.