I'll have to test it out a bit when i get home from work. I havent noticed it breaking faster or more often when i'm in melee range, but, I'm really not usualy in melee range. When i get surprise pops / adds if i dont want to mez, i'll usualy DoT 'em with time.. time... erm that one that has 60% slow, run a few meters off then use simulacrum. works great for me
On a kinda related note, i've realized i dont really need to use simalucrum too much even when soloing. Hit 'em with the slowing dot, and just run in a big circle while your dots tick away.