Soldier Psyker, Arch militant or Master Tactician?

Just about to get my second archetype and is playing a Psyker soldier who is using pyromancy. Would you recommend going for arch militant or master tactician? I've heard master tactician is really good as it does a lot of damage on a single attack but I really like the feel of using diffrent attacks so is drawn to Arch militant to, which of them are better?

also depending on which route how would you recommend building the character regarding

1. Tactics,
   
2. Abilities (what pyro abilites to choose and if i should get another psyker dicispline). I notice that I have a couple action points left after doing my attacks so maybe get something so those dont go to waste?
   
3. Any good items to keep in mind to find