Originally Posted by
Endus
It's definitely a good option for an Orc. It wasn't included in the BiS list because that's only true IF you're an Orc, for one (otherwise, Mastery is going to provide slightly less of a return than the Haste on the Carapace Breaker), and because it's an expensive craft, for two; 5 spirits of harmony aren't cheap or easy for everyone to arrange at this stage of the expansion (and the list won't be too relevant much later). The crafted shield, by comparison, is much cheaper and easier to craft.
Also, as a more general aside; I've updated the guide with the trinket ratings that Binkenstein worked out and posted this morning.