It varies by instance, mainly because of how many other people you have around you. In 4v4, BLM is horrid to play, quickly built up resistance to bind and sleep, easy to get picked off. Secure is a little better, but once a melee/brd has their sights on you it's annoy and run away time. Slaughter casting is not an issue because there are so many people packed together in a small space that nobody can single you out and shut you down.