[Shard of Contempt] (44 rating) is good, but not current end game good.

If you have no expertise on gear, not human sword rogue, then this trinket is supposedly on the order of the [Dragonspine Trophy], maybe just a little under, and a little above [Ashtongue Talisman of Lethality] and [Warp-Spring Coil].

But rogues have a talent to give 10 expertise (39.4 rating) in combat, those talents cannot be moved anywhere else that would give a dps boost, so pretty much stuck with em unless ppl really wanna add pvp tricks into the build.

Looking into endgame, [Shard of Contempt] will diminish in value just because of items like [Slayer's Boots] (24 rating), which are best in slot.

Boss dodge = 6.5% = 26 expertise required = 102.44 rating.

Standard combat rogue cap = 102.44 - 39.4 = 63.04 rating.

So if you wear this trinket, it only gives you 20 expertise rating room left in gear, which can be filled up easily in current end game.   Not to mention human sword rogues, which would give you bonus 5 expertise (19.7 rating). 

Also, right now, rogue testing gives it around a 1.2ppm still with 40-45 sec internal CD, which mathematically gives it an equivalent 92 AP static AP for us.

So, it's among the best trinket in game for rogues, for now, until you gear up in Sunwell.   But even after that, this trinket probably makes a great levelling trinket, and just might last to level 80 since expertise caps will be raised by then (though they might make proc rate decrease as you lvl, who knows).