I haven't seen it yet and without giving any of the story away would you say it was as good as '28 days later' or better.
I enjoyed '28 days later' and the DVD has an alternative ending on it, for those who haven't seen the first film yet
SPOILER COMING UP:
In the alternative ending, Jim dies and his character is replaced with a chicken (I kid you not
)
END OF SPOILER.
You are right about Robert Carlyle, he is a great actor and very good at playing the psychotic type as he did in 'Trainspotting' and in 'Ravenous', you never can tell when he's going to go nuts, so there's always a tense atmosphere when he's on-screen.