First glances and impressions leave Stone Armor seeming lackluster and a bit clunky. There are alot of drawbacks in the form of -Speed, -Damage, and -Recharge which look very unappealing. However, if looked at from a different perspective, Stone becomes a set that requires finesse to use, but can be unbelievably powerful. And one that won't bore you pre-32 since the armor shifting keeps you on your toes.
There are 2 gems in Stone which IMO put it in front of the other sets.
The first is obvious - Granite Armor ; Gives status resist that I've never had broken (and I've had stun icons stacked under my health bar 5 rows deep,) 4 SO slots for Damage Resist give you the 90% (3 HOs get you to 95%) cap to all but Psi, leaving the other 2 slots for added Defense to all but Psi (base 20% 2 SOs get your 28%, 3 HOs get you 34%) The -Recharge can be helped with (semi)Perma-Hasten, and the fix for the -Speed is the same for Rooted. The -Damage however means you will never be a 'heavy damage tank' with Granite running. This is one reason many people keep the other armors (especially for soloing) after they get Granite.
The second is a bit dusty at first and will give you your first taste of comprimise - Rooted ; Base heal of +100%, 6 SOs get you to 300%, 6 HOs get you 400%! Plus Rooted is awesome status protection to all but Immob (which can really piss you off.) Rooted makes you a Regen tank, and a kick-[censored] one at that. Earth's Embrace + Rooted also ups the amount of health regen'ed giving you a 40% boost to your heal rate per EE you have up. Also in I4, Rooted provides Res to End drain. Freakin golden.
The comprimise is painfully obvious the first time you turn it on. I just laughed in digust as I walked for what seemed like minutes to get to the door I was 20 ft away from when I turned it on. The correction is simple - Swift slotted up. Some people say 3 is bare bones minimum, I say no less than 4, and I ended up at 5 comfortably. My reasoning was that my teams would get tired of waiting on me for every fight, so they would start w/o my getting to set up and doing my job gaining aggro and positioning mobs right ( my worst nightmare.)
So many people wonder why even keep the other armors after Granite. Other than the fact that you could never EX below 33, it's up to you. Here's what you'll be losing -
Stone Skin - Marginally useful pre-Granite. After that it's a waste of a power since Granite caps you making SS redundant. It also only gives a base Res of 12.5%, less than useful IMO.
Rock Armor - You have to pick a power at level 1, either Stone Skin or Rock Armor. RA is 10-fold > SS to me. If you ever want to tank Psi, you need RA. So what if you have to 6-slot it (all DefBuf), if you're going with minimum armors (which to me = 4 armors) you're still dumping alot of slots. Live a little. You only get out what you put in. And other cheesy cliches. It is worth a note that in PvP the Def of Rock Armor vs. the Smashing damage of Brawl makes your toggles harder to drop.
Earth's Embrace - You can go your entire career without this power and not really gimp yourself, but I don't recommend it. With Rooted it not only gives you the initial heal and added HPs, but it increases your regen rate. Healing is what sets Stone apart.
Without the -Recharge of Granite you can have 2 EEs up at least the majority of the time (I can't swear to this since it's still something I'm toying with, but the math supports it) with Perma-Hasten and 6-slotted Rech. With Hasten, Rech's, and Granite it's easy to keep at least 1 up all the time. Admittedly not neccissary, and some couldn't imagine slotting EE at all and use it as more of a "ok, that may be too many" power (I recommend holding off on slotting, if you do, until the last few levels) It does come in handy as a stop-gap measure to keep you alive during a pull more massive than you can handle until your team can thin out the crowd a bit.
Brimstone Armor - Has its uses, but is largely a throw-away power. Both Fire and Cold are seldom a problem, especially since Rooted's heal generally soaks up the damage. After Granite you will really only need the other armors. The only Psi using group that also uses Fire is Carnies, and Schneshals (or whatever) are hardly worth woring about unless you've herded a ton of them, which would mean you have bigger fish to fry since they usually represent only 10% of a mob. 50% Res to Fire/Cold can be capped with 4 slots(Dam Res), 3 HOs, or 2 HOs + 1 SO. If you do take this power, please don't abuse slotting.
Again, this power is worth a PvP note as my Fire/Dev will kill you quickly without any sort of protection.
Crystal Armor - Second most prevelant damage type in the game is Energy. Crystal is one of the must-have armors if you are ever going to tank outside of Granite. Also protects against End Drainers with Def. 6-slot all DefBuf.
Mineral Armor - The only Psi protection among any tank. Makes you a situational "best friend" to anyone trying to take down Mother Mayhem.
I hear of alot of people only taking Mineral and Granite and I just can't figure out why. Novelty maybe, but just because you can doesn't mean you should. You could tank Neuron with only Crystal, but that would be....well....dumb. If you want to tank Psi, you will need Rock and Crystal to cover your bases. Minerals alone does not a tanker make. 6-slot all DefBuf.
Also to debunk an all too common rumor, Mineral does not stack with Granite.
I didn't include Mud Pots in the "what you'll be losing" section because it's not an overwhelming gem, but it's no slouch either. It is a must-have. It can be your minion killer (though be it slow,) but on top of any other reason to take this power lies the fact that it is without a doubt an awesome aggro magnet. It damages, taunts, and deals status effects, all of which work together to make this one of the best tank auras in the game. Try to do without Mud Pots and your abilty to hold aggro will deeply suffer. 5-6 slot 1 End Reducer, 4-5 Damage.
To get proper mobilty while tanking, I'm sorry to say, Teleport is almost mandatory. Without it, and without the ability to jump, you will continually find yourself saying "Um, come and get them here I guess. I'm stuck."
Also Weave really helps with Granite, giving you godlike tanking capability, though it is entirely unneccessary.
After playing Stone Armor for a while you'll find that, what at first seemed a modgepodge set of powers, it is an efficient and absolute tanking machine.
