I got this about 2 weeks ago, and I have to say, I do love it.
I mainhand with RB offhand, and this procs like mad. Of course, in a group without a good taunter, (see: Paladin or SK) I take my fair share of hits.
The significant advantage of this proc however is the snare. The poison only adds 7.5dps, but in zones like PoV and such where mobs flee, and in groups where you can't always get a Ranger, the proc is invaluable. Even unbuffed (DEX low 200s), this will proc 2-3 times in a fight, and buffed with 280 DEX, I've seen it hit 10 times or more in a single fight. That gets a lot of taunt, but hey, we get evade for a reason.
In a solo situation, this thing can make life a whole lot easier, or in the off chance that you get jumped while crossing a zone, the proc can save you easily.