While the chance on hit of this item isn't bad, the stat is way under par for level 80 (assuming you are thinking of using it for end game.) and I don't know of any other with a similar chance. There are many good trinkets around with good uses and procs that will give atleast twice the stat bonus wether it be agi/crit/haste or whatever you are looking for.
"Your melee strikes have a chance to increase your critical strike rating by 258 for 10 sec." chuchu's tiny box of horrors is NOT a good hunter-trinket...
My guild is currently in the early endgame (Naxx 10 mainly), but I use Death Knight's Anguish and I love it. When it procs, my crit gets as high as 50%+ for 10 secs minimum. Each burst of explosive shot equals an attack for effect stacking purposes, so for SV hunters like me it's choice.
I'm not uber elite or anything - I do this for fun. But I hit 2.5k DPS on the Patchwerk fight with this and the +50 crit rating/heal on use trink.
2.5k isn't much special though... And you don't want to be using green trinkets when better blues/epics are available everywhere. (Keristrasza in Heroic Nexus, the emblem trinket, Loatheb's shadow, Fezzik's Pocketwatch etc)
Having a crit on proc trinket is fun, I'll admit that. But it's stupid to keep using it just because your crit% is so high when it procs.