Question about warlock stun skills

[aishsharma]

Is there any point in taking them beyond level 1? I mean there is no stun immunity, duration is same and i don't think high level stun has higher probability of landing does it?

[XMoshe]

It does, the more difference between the lvl of the skill and the char or mob you use it on the less chance it has of actually landing/having the duration shown in the description.