Unarmed investigator help?

[Chromascope3D]

So I was looking to make an unarmed-focused Investigator, so I was looking to take a dip into either the brawler, unchained monk, or Master of Many Styles monk, but after weighing the obvious pros and cons of each (and I am aware that MOMS was nerfed so that it wasn't the be-all end-all that it used to be), I'm still unable to make up my mind as they all offer something that appeals to me.

So, which of these would you recommend and for how many levels? I'd also take suggestions for anything else that could work in this regard.

[eldskald]

Monks can't flurry if they're using armor, so you'll have to go with brawler. Also, you can't get dex to damage with unarmed attacks, so either you will deal little damage or you will build strength instead of dexterity. Do you intend to be sneaky? If not, I would build strength and get 2 levels of brawler. You would scale off of strength and intelligence and without the dexterity feat trees, you would free up space for power attack, medium armor proficiency and heavy armor proficiency. This way, you have as much AC as the dexterity ones (even more in fact), though you will move slower and have less reflex saves. You can grab the Fleet feat if you want to fix speed. With flurry and strength, you certainly hit a lot harder, and carry a lot of equipment too. There is also a secret tech about being a strength character instead of a dexterity one: you benefit off of enlarge person! That's a huge thing in my opinion, it's one of the best lv1 spells and stays useful all the way up to lv 20 (unlike color spray and sleep). And as an investigator, you can prepare them as extracts right from lv 1.

With the empiricist investigator archetype and student of philosphy trait, you will do knowledge checks, perception checks, disable device checks and social checks with intelligence. Because intelligence also gives you skill points and you have inspiration, you will certainly be the supreme skill monkey for these. Add in pragmatic activator and you will also use magic device off of intelligence. You will suck at sneaking and stealing because you won't have dexterity and will be wearing heavier armor, but since you are an investigator you can just prepare an invisibility extract and do the scouting if necessary. Oh yeah, and grab the mutagen discovery with an investigator talent to kick ass. If you want, you can use the snakebite striker archetype for brawler to trade martial flexibility for 1d6 sneak attack. Martial flexibility is cool too, so it's your call.

[Ellrin]

Honestly I think the best unarmed investigator is probably a natural attacks investigator. Right from 7th level, you have access to the monstrous physique line of spells (extracts in your case) in combination with the bonuses to hit and damage from studied combat. It's a shame by RAW you can't get access to the inspired weapon quality this way, but at seventh level you have access to forms with five natural attacks--which increases to six at 10th level. Add another natural attack in through a feat or magic item (Spirit Oni Master (http://www.d20pfsrd.com/feats/general-feats/spirit-oni-master/) or Helm of the Mammoth Lord (http://www.d20pfsrd.com/magic-items/wondrous-items/wondrous-items/h-l/helm-of-the-mammoth-lord/) will give you a primary gore), then add in your iteratives through something like Improved Unarmed Strike or Weapon Proficiency (armor spikes); and then with haste and multiattack, and you've got two attacks at your highest BAB, seven more at BAB -2, and then your usual penalties for successive iteratives. Taking studied combat into consideration, you can afford Power Attack or Piranha Strike pretty easily. Heck, you may even be able to afford both.