I have seen it and I would say it was pretty good.
A fairly typical zombie affair based in 1 building, dont expect much story but the action is pretty relentless and exciting to watch. Actually there are hints to a deeper story but these are not developed much at all, in fact its refreshing to see a film that doesnt try and spoon feed the audience. Its kinda left to your own interpretation.
The subtitles dont interrupt the film at all. I would reccommend this film as definitely worth seeing.
The yanks are already in the process of re-making it, they call it 'Quarantine' and it will be out later this year. I'm pretty sure they will dumb it down though so I would watch the original first.