My one question in regards to this is on mod-slots. I've always preferred mitigation over health, but with the mod slots, going from "27B" to "27",it's a trade of 22 endurance for 10 of the tank stat and some of your primary.
I *always* go for the unlettered mods, given the option. More mitigation is more better, as I see it, and I'd rather get redundant damage (for faster kills) than redundant HP (for... nothing much really; slightly better self heals, I guess?). I've never had a problem surviving even though I've got sub-24k hp, and I've never had a problem generating threat (I've actually generate so much threat that I have to tank first in any 2 tank scenario because, otherwise, I just steal aggro from the other tank by overcoming his opening volley). It's for the same reason that I prefer to use Resolve Armoring and Hilts as opposed to the Force Wielder I'm "supposed" to use as a tank. As I see it, Endurance is for chumps. Mitigation>Damage>HP is my prioritization.