the effect of flunitrazepam is totally different. i didn't like it, slept 30 minutes later (like switching off the TV).
Effect changes when used over a longer period. If you want a really strong benzo, which will not knock you out, then go for e.g. clonazepam or oxazepam.
But it depends on the effect you want: some are used by epileptics, some to sleep, some to calm down, some to ...