I've had great luck upgrading horror movies to blu-ray. Often even upgrading them to better DVD versions.
When it comes to selling movies, the horror titles are the ones that actually sell. Even inferior editions. I've actually made a profit on upgrading several older titles to either blu-ray or a superior DVD release.
So I generally always upgrade the cult titles (Night Of The Demons 2, From Beyond, Ticks, When A Stranger Calls, Intruder, Dark Night Of The Scarecrow, etc), because those can usually pay for themselves.