To non-Paladins: Hammer of Justice is an on-GCD stun/interrupt that is on a 60 second cooldown. With 2/2 Improved Hammer of Justice and 2/2 Judgements of the Just this could be taken down to 20 seconds in 3.2, however as of 3.2.2 it can now only be taken down to 30 seconds.
It was primarily useful as a backup plan when an interrupter was late or dead or something and for Faction Champions as pseudo-CC. With the nerf (thanks again, PvP!) I can either choose to have 30 second HoJ or 50 second HoJ and the improved Sacred Shield. I typically do have a Holy Paladin keeping SS on me, however, so the main benefit of Divine Guardian would be for the better raid wall which is also only useful for certain fights.
Not decided which to go for yet, but eager to get a few opinions on the matter.
This is the definition of a personal choice, primarily (in my opinion) depending on the skills and strengths of the people you raid with. Do you offtank a lot and find yourself in situations where you use DS? I'd go DG then. I've had 2/2 Imp HOJ ever since 3.0 hit and I am cringing at the idea of giving it up, but 30 seconds last night felt like a LOOOONG time. The last consideration is that since 3.2.0, Reckoning is no longer a TERRIBLE talent. It's still our worst threat talent - but since you have 3 points to play with to get past that tier, 3/5 reckoning is a decently popular spec these days for single target boss tanking. Reckoning also gains value if your'e using the new Quel'serrar, which is slower than most tanking weapons, or a slow 1handed DPS weapon, since the extra swings get stronger with a slower weapon.
It's purely flavor though. I'm still keeping HoJ, but if you maintank a lot and could use the threat clearance, even reckoning is acceptable these days.
I must admit I hadn't really considered 3/5 Reckoning so thanks for that. Like you, I primarily MT so raid wall is usually only used during things like Mimiron Phase 2 or the Faction Champions fight - it's rare I'll use it for my usual role, which leads to it being somewhat situational.
The patch hit today in the EU and we did FCs (therefore HoJ was used on basically every CD) and 30 seconds really does feel like a lifetime. Overall 3/5 Reckoning probably does fit my general duties better than either option but the thought of waiting 50 seconds for HoJ just plain upsets me.
I'll stick with Imp HoJ for now I reckon (since it doesn't require a respec and I'm lazy) but I may try out Reckoning to see how I get on so thanks again for the suggestion