I've been debating the value of getting the BoA chest pieces for the toons that I'm still working on leveling to 80. My original main, Joar, is about 65% complete with the Argent Tournament dailies needed to get to Crusader. I've also got Exalted with 2 of the 5 factions needed and am at least half way through Revered on each of the other 3. Even thought that doesn't sound like much, I'm still debating whether Crusader is worth finishing from a sheer time value standpoint.
Of the toons that I have remaining to level, the same BoA chest piece can only be optimally used on a maximum of two toons. Assuming an average leveling time now is around 8 days, or 192 hours, an additional 10% xp bonus should save me around 19 hours on each toon, or 38 hours total for each of the toons.
Doing the Argent Tournament dailies takes at most an hour and a half each day to finish and with 8 days worth left, that works out to 12 hours invested. The only remaining question is how long it would take to get the remaining three factions to Exalted. If I could do it in less than 26 hours, it seems like it would be worthwhile.
If I only had one toon that would be using the chest piece, the value becomes less clear.
After patch 3.3 drops, I think badges will actually be the preferred route for acquiring these items rather than Champion seals. If the average heroic conservatively takes an hour and drops an average of 4 badges, it should only take 10 hours to accumulate 40 badges, which should be less than the questing time it takes to accumulate 60 Champion Seals.
So my conclusion is that it's worthwhile to continue to work toward Crusader on Joar until patch 3.3 comes out because the time saved in leveling my mage and priest should more than offset the time invested on Joar. After that, I should be able to get by with just acquiring the plate BoA chest piece for my paladin and warrior and just have the the shaman use the leather piece that my druid used.