I actually think the Breastplate of Tormented Rage is pretty good compared to the Valorous tanking chest, that is, especially if you could use the extra hit rating. The main reason why I don't use it in my main and/or threat-centered sets is really the fact that (other than Valorous gloves) there's a non-set item that's superior to the Valorous piece of the same slot for threat statistics, and I prefer this chest the least compared to Helm of Vital Protection, Pauldrons of Unnatural Death, and Legplates of Sovereignty versus each of their counterparts. Thus, I use Valorous Chests + Gloves still to maintain the 2pc set bonus pretty much exclusively, and find the extra hit (or expertise even for that matter) elsewhere if I'm looking to cap out on them or build a threat set.
In short, I think it compares to the Valorous chest quite favorably (especially for threat/avoidance -- you're just losing the block really), but when looking at the bigger picture there's other non-set items that I prefer more to their Valorous counterparts, and thus I still often find myself using Valorous chest 99% of the time to maintain my 2-piece set bonus. Additionally, you never know what 3.1 and beyond may introduce where you might thank yourself for having all 5 Valorous pieces just to be more flexible with keeping your set bonus(es) while upgrading to new non-set gear in Ulduar or what have you.
Take that for what it's worth, just my 2¢, and hopefully it made sense. Good luck.