Resisted about one time in four at level 65, though. I've been recasting at 90 seconds just in case I get a few resists.
Otherwise nothing difficult, just FD split then a ton of hit points to burn through and about a blue of AA XP per kill. No other DoTs have been resisted yet (saryrn's kiss, funeral pyre, splurt, blood of thule).
within 2 hours of getting lvl 62, and never having been to HoH before, i was kiting these things aroudn the GY. easy kills, if youre calm about it. takes me about 5-6 minutes to take one down depending on my dot lineup, try to never get hit, that hurts.
currently getting 6-9% aaxp per kill. but sooo boring.
i also noticed a little bit of fire resistance in them, helps to throw a FR debuff on.
Can be snared/rooted. Can be mezzed. I assume they can be stunned(with an appropriate level stun) but am unsure. Slowable(mitigates my 70% slow a little). Cannot be charmed. They don't summon. Not undead, or so said the pally.
PH's are A Protector of Marr/An Animated Guardian
I've never seen them drop anything besides pieces of armor. I have however seen their friends that spawn in the same spots (animated/protectors) drop the Defender's Lightblade, if the guardians drop it too its very rare.