Jul 22nd 2008 10:27AM "And while Dreamless Sleep saw some use in 40-man raids in the old world, I don't hear about it being used much in BC - anyone a fan?"
Mostly horrible for use as a healer, but great for use as a DPS (though it was dispellable at one point, I am not sure if it still is, and you risked it being cleansed or dispelled from you) -- I had a handful of these on my hunter after levelling alch to 375 and they saved my backside a couple times solo and were useful a couple times in instances. Specifically in situations where I could not Feign/drink (usually because of FD cooldown). Not as useful for classes liable to take direct damage solo though obviously. I can see it being almost as useful to DPS casters in raids; if I was on my mage and too close to top of threat, and nearly oom, I could use this instead of a Super Mana Potion and get more mana back to save evocate for later, which I usually do just before or just after invisibility in raid boss fights. Not always possible in fights that require a lot of movement in particular phases, but worth looking for the opportunity.
As far as healing goes I have only ever used them on my priest in Gruul's Lair over a year ago, after throwing Renew on the tank right before the Silence effect. It was definitely better than a normal mana pot, but I was also raid healing and not tank healing, which could have gone horribly if I was asleep at a crucial moment.
In short, they're more useful than people think.
But I tend to use the mats for other valuable things.