Primaris Psyker, an HQ choice I have used quite extensively, although admittedly not perhaps to its most optimum, especially in 6th edition.
My own Primaris Psyker- An oldy, but a goody!
Since the introduction of allies with 6th edition, the poor Primaris Psyker seems a little bit underwhelming. Why would you take a Simple Mortal, when you could have a Rune Priest...or Tigarus (who seems like he is going to get a lot more game time these days).
Even within the I.G codex there is some stiff competition for HQ slots- The command squad,which can act like a light veteran squad and can augment squads with orders throughout the game and the fearsome Lord Commissar with his leadership bubble.
So, again...why choose the Primaris Psyker?
Sometimes you just need a cheap option to fill out your HQ slot. Yes a bog standard company command squad is cheaper, and the Lord Commissar has the same base cost, but both these units need points spent on them to make them usable.
The Psyker at his base cost already has some functionality. He has access to psychic powers and also can be hidden in units as he is an independent character.
With the use of 6th editions power choices his utility against a variety of opponents is increased without having to increase spends, but he still has his default settings if you feel you just want to keep things straight forward.
If I'm being honest, there is already a terrific article written about the Primaris Psyker's power choices that I could not hope to better. It can be found HERE. Suffice to say, I agree with the writer that the best choice of psychic powers is the telepathy table. Puppet master is extremely useful and the Psychic shriek, whilst risky and short ranged is a combo I would love to try with the Primaris and a Psyker Battle Squad.
That said the article does say that the standard codex powers aren't exactly powerful enough for competitive play. Whilst again for the most part I would agree there are better ways to spend your points, I have to mention one combination I have enjoyed using in my army.
The Strength Six Gatling Gang...
Firstly let me say, I love grenade launchers. I think strength six is brilliant, and guard can bring it in spades for not a lot of points. Against marines a shed load of strength six is just as effective as a shed load of auto cannon fire, and against toughness three or lower is instant killing as easily too.
That said then, I like to start with a bog standard platoon (everyone's gotta have one. :))
I equip the command squad with 4 grenade launchers. I then like to stick them in a chimera. Already this is a mobile bunker with 7 strength 6 shots a turn for just over 100 points. I then add in the Primaris. This gives me the potential for an average of an extra 7 strength 6 shots using the standard power. That's gives you between 9 and 19 strength six shots per turn.
Is this game winning?
Well no, it's not. But that in itself is helpful. By keeping the points low and the threat level low, but still chucking a lot of mid strength fire power down range and remaining mobile, your primaris psyker is quite likely to survive. This is a huge bonus if you are using him as your warlord. I have used this tactic regularly and it does tend to work. Plus at 175 points for the whole unit, that is quite a serious moving pill box. It is particularly effective against light armoured fliers like dakkajets and crucially, the unit can score (just don't forget to bail out and hug the objective.
So the Primaris Psyker is far from the ultimate choice in HQ's. Honestly I think the best choice for HQ is the Company command squad. That said however, I think the Primaris Psyker has his place. Often I have chosen him to free up points for my other selections. As targets go, there are more threatening choices before him, so he forces your opponent to make choices which otherwise would not be there. Do I take out the cheap, relatively un-threatening warlord, or do I deal with the veteran squad with plasma guns that will surely be my demise next turn?!?
I say give him a turn and you might not be too disappointed. The extra points and the varying utility often pay off.
Let me know your thoughts. As always I've only been able to apply my own experiences, so I'm interested to hear yours!