Psionic Aegis or Power graft armor

[keeper2161]

My plan is to be an Elan Soulknife. Is prestigeing into the Metaforge class worth it? I can get the archtype gifted blade and get the power graft armor. With mithral and grafted armor it would turn full plate into a light armor, +9 AC with a max dex of +4 (up from 1), a -2 skill Armor Check Penalty (down from 6), and with a 15% arcane spell failure (down from 35%). Plus anything else I can put on it. It would be expensive but all the money I would put toward weapons would go to the armor. I would be losing class features from the Soulknife for something I can do with enough money and one power. But I am not an optimizer and I relatively new to pathfinder and have read maybe 2 books. Am I missing something and is the Soulknife/Aegis/Metaforge worth it?

[Manyasone]

The power does not really compare to what an astral suit can do. Not even close. The metaforge is a no brainer if you take both soul knife and aegis. Just remember to also take feats 'student of the astral suit' and 'fighters blade'.

[keeper2161]

What would you suggest for a build then? I have heard 3/3/3 but I don't know what that means. Is it take three in each until level 9 or follow that rule until 20?

[Manyasone]

The earliest you can start taking it is at three levels of both soul knife and aegis.

[pi4t]

The Aegis puts a lot more focus on the Astral Suit than the Soulknife does on the Mindblade, so Metaforge works out as more "Aegis with a Mindblade too" rather than "Soulknife with an Astral Suit". It's very good at doing that, especially if you mix in the feats that Manyasone mentioned (which, to save you looking them up, progress your suit and blade respectively by 4 levels, up to a cap of your character level). If you're only interested in the astral suit as a small addon to a soulknife's abilities or for its defensive capabilities, then it's probably not worth it.

However, I think you've misunderstood the abilities the Astral Suit offers, if you're comparing it to buying an armour. While it can do defence and act as an armour, and this is well worth it at low levels (when you can't afford anything better anyway, and don't yet have any other enhancement bonuses to your ability scores), Astral Skin form doesn't prevent you from wearing other armour underneath it. Thus once you get some money, it's better (particularly for a metaforge, who has more money to spend due to not needing a weapon) to buy a decent armour, and spend your customisation points on more interesting things, like flight, reach, powerful build, stalwart/evasion, the harness power stone line (which effectively gives you a list of powers known), etc. The armour versions are still useful in situations where you need armour now (eg ambushed while sleeping), or you can't bring your normal armour (eg slipping into a social event, or when captured and disarmed). Pure Soulknife gives you more raw offence in ideal situations, but metaforge gets a lot more options for when "hit the guy right in front of you" isn't what's needed. This is true even if you take the gifted blade archetype, although the gap is less and you'll have fewer power points to throw around at high levels.

As for build, I'm not sure what your source meant by 3/3/3 either (are you sure it wasn't 3/3/n or something? Or a specific build for 9th level?) but my advice would be the following:

Level 1: Aegis or Soulknife. Aegis is probably mechanically stronger at first level, but flavour and backstory will probably be the determining factor here.
Level 2: Whichever class you didn't take at level 1. Probably not, strictly speaking, the best option mechanically (especially if you started with Aegis), but it means you can introduce the key idea of the build - "summon all the gear" - early on, which is better for flavour I feel. You also get to have a masterwork weapon which counts as magic, which is 1 damage short of the best everyone else will have until they can afford +2 weapons - at about level 6, judging by the WBL table.
Levels 3-4: Aegis. As I said before, it offers significantly more to low level characters than Soulknife does. It also gets more from its "progress the key class feature while taking levels in other classes" feat, so it's good to take that one early. Speaking of which, see if you can talk your GM into allowing you to retrain a feat into Student of the Astral Suit at level 4.
Levels 5-6: Soulknife. Take the Student of the Astral Suit feat at level 5, if you weren't able to get it before. Now the first 4 levels you take in Soulknife will also progress your astral suit, meaning you have most of the class features of an Aegis of your character level, as well as getting Soulknife abilities. Again, see if you can retrain a feat into Fighter's Blade.
Level 7: Aegis or Soulknife. Take the Fighter's Blade feat if you couldn't before, and your mindblade will suddenly become equivalent to that of a soulknife of your level. Since the feats work for four levels, you effectively have one free level of not-Soulknife and one free level of not-Mindblade where you get all the abilities that metaforge gives you anyway. Might as well make use of them.
Level 8: Whichever class you didn't take at level 7. See the above. You're now counting as a level 8 aegis and level 8 soulknife for the purposes of astral suit and mindblade.
Level 9+: Metaforge, at last.

Alternatively, if you have some other 1 level dip you like the look of, you can do that at level 7 without missing out on progression of your key abilities, and then start taking Metaforge at level 8.
Obviously you won't get many favoured class bonuses, but it's worth mentioning that those you do get should probably be poured into power points if you're playing a psionic race. You're going to be kind of starved for them with a metaforge build, which is one of its weaknesses.

[keeper2161]

Thank you for this detailed response. When taking blade skills is it character level or soulknife level?

[legomaster00156]

Soulknife level is what determines prerequisites for blade skills, but remember, Metaforge advances that.

[digiman619]

Also of not is the Natural Blade trait from Psionics Expanded: Soulknives,, which is essentially Magical Knack but fro Soulknives, giving you an additional 2 levels you can multiclass way from it.

[keeper2161]

The metaforge doesn't say it increases the level for the prerequisite for blade skills. Also what is natural blade? I have googled it and I have found nothing about it.

[legomaster00156]

Ah, forgot that it only does that for aegis customizations.

[digiman619]

The metaforge doesn't say it increases the level for the prerequisite for blade skills. Also what is natural blade? I have googled it and I have found nothing about it.

As I said, it's in Psionics Expanded: Soulknives. I don't think it's on the PFSRD yet. I will post the text here for reference.

Natural Blade (Psionic)
You’ve learned to continue some of your soulknife training even when exploring different trades.
Benefits​: You add +2 trait bonus to your soulknife level to determine the strength of your mind blade enhancement and access to blade skills as if your soulknife level were two higher (this does not improve blade skill effectiveness, only your ability to meet prerequisites). Your effective mind blade level cannot exceed your character level. The character must have the enhanced mind blade class feature (or its equivalent) to actually receive the magical enhancement bonus to the mind blade.