For an alliance twink tunic of westfall is better imo, considering you dont have to reach 7 percent hit like horde do, so the extra hit isnt worth the agility lost.
Here are two alliance chardevs I came up with:
Heres the first one with tunic of westfall:
http://chardev.org/?profile=293768
Hp:1261, hit chance:5.54 percent, AP: 553, crit chance: 44.44 percent.
Heres the 2nd one with the boa chest piece:
http://chardev.org/?profile=293774
Hp: 1291, hit chance: 7.06 percent, AP: 547, crit chance: 44.04 percent. ( since I already have more than enough hit with this build, instead of ellos I went with a 2nd argas to even out the gap in crit and ap from the first build, and as a rogue dps class who the hell wants more stamana at a loss of ap? Stam stacking is bad mmk.
So, with boa chest you gain 30 hp which is nothing, you go over the cap by alot which isnt needed, and you lose 6 ap and a small amount of crit.
Its really a toss up between wanting a slight amount of hp or a slight amount of dps stats, and imo as a rogue those dps stats are worth more than 30 hp. 30 hp is nothing, one auto attack from an opponent will take that x3-x15 away.
For alliance tunic of westfall is viable. Only horde should be using boa chest as it has more hit, and peaple who didnt happen to obtain a tunic of westfall before it got grandfathered. If you have it, use it in my opinion.