yes there is - if you planted it and are in range the icon is highlighted and full color, if your out of range it's not highlited On the whole I like it and it's got some nice utility but a longer timer and possibly shorter cast time would make it much better.

It seems to work pretty well for me, i've tried both and they're really similar in survivability and dps... the extra DPS from DF and thrash crits from claws of decay make up for not getting chain shocks. Also the utility gained from 30 yard DF and the 10 sec off electrocute is nice. I prefer DF over whither for the range, you also get a little more burst between DF and the thrash crits

Using this Darkness/Madness thrash hybrid, pretty close to what I was using pre 2.0. Lots of survivability and utility with pretty good DPS... DF and spike out of stealth are just too hard to give up. The Darkness/Deception build does look fun single target though, and getting fade does give you a little more CC utility for stealth > spike. http://www.torhead.com/skill-calc#200rIrkddfzMdZZfrzob.3