General

It's most useful for Shadowers, since they're melee fighters they take a lot more damage so the ability to heal is more needed, Night Lords can use it now that they lose Drain though, it'll help out a lot at places that have potion cooldown, and it's useful but not nearly as useful for Dual Blades as it is for other classes. They already get Life Drain, but Vampire heals /so/ much more.

[quote=Clashofpower]What he said^
It's the same for most skills. Good, but better at higher levels[/quote]

Is it worth the trouble/time to get it maxed?

It's useful at level 1 but not nearly as useful at lvl 5