Just watched the trailer (via post no.1 above) and all I can say is I'm definitely seeing that film when it opens in August in UK cinemas. I can see that getting an 18 certificate, as based on the clips from the trailer the death scenes could push the certificate up from a 15 to an 18 this time. And the death scenes in the first three were pretty gory, and they were all given 15 certificates!
The Final Destination movies are one of the few horror movie series in the last 10 years which have been one of the better ones. It was helped by Glen Morgan and James Wong who built the foundations with the first film 10 years ago (I'd forgot the first one came out in 1999). Before that film they had done great work on The X Files and Millennium.