The TIE/FO is the First Order's update to the classic TIE Fighter. It costs roughly 3 more points than a standard TIE Fighter with the same PS, but comes with 1 shield and the Target Lock action, making it a pretty good deal. They also have access to a Tech upgrade slot. This gives them some unique abilities compared to the standard TIE Fighter, but will make them significantly more expensive.
The TIE/FO has a similar movement dial to the standard TIE Fighter, except that it makes the 2 Turns green and adds some 2 S-loops. These are both excellent changes and make the TIE/FO better at close range dogfighting than its predecessor. In fact, you can think of the TIE/FO as intermediate between a TIE Fighter and a TIE Interceptor.
The base TIE/FO is the Epsilon Squadron Pilot. With PS 1, he's a good blocker and is both more durable and maneuverable than an Academy Pilot, while Target Lock allows him to hit a bit harder. He's a great choice to fill out a list or use in a basic swarm. Weapons Guidance is a good option for this pilot, as it guarantees that he can use a Focus token to generate an extra hit even if he doesn't roll any eyeballs. A swarm of TIE/FOs with Weapon Guidance actually has hitting power similar to a swarm with Howl Runner, but without her vulnerability.
The Zeta Squadron Pilot is similar to the Epsilon but costs an extra point for an extra 2 points of PS. Not a bad deal if you have the extra points, but it doesn't bring much to the list beyond shooting before other basic swarms and avoiding some damage against Predator.
The Omega Squadron Pilot costs an additional point compared to the Zeta Squadron Pilot for the addition of 1 point of PS and the all important EPT slot. This makes them both flexible and efficient for their cost. They'll most commonly be run with Crack Shot and possibly Weapons Guidance to give them reliable offense. For a few points more, you can also take Juke and Comms Relay. This combination allows you to save an Evade token between turns, which Juke then allows you to use to modify enemy defense dice. This provides almost as much offense as the first build with some extra defense at the cost of 2 more points.
Epsilon Ace is only PS 4 but gets to pretend to be PS 12 as long as he doesn't have any Damage cards. This makes him a budget ace hunter. He only has a tech slot, so you're probably best off taking a Comms Relay or the upcoming Sensor Cluster to keep him safe longer and maintain that PS 12.
Zeta Ace comes with an EPT slot as well as the ability to use the 2 straight template when barrel rolling. This sounds great for repositioning, but I personally haven't had much success with it. I think that's due to lack of experience, as you have be able to visualize that 2 barrel well as you plan your move in order to use it well and I can only see the 1 in my mind.
Epsilon Leader is basically a TIE/FO with a Wingman aura, removing 1 stress from every friendly ship in Range 1. He's useful in any list where you will be flying in formation and stressing. I've tried to fly him along with some Push the Limit Interceptors with mixed results. Being able to remove their stress really opens up their dials, but their Boosts and Barrel Rolls mean that they really don't want to fly in formation. Therefore, I spend most of the game trying to get Epsilon Leader in the right spot to help my freewheeling aces. It's great when it works, but that's not too often.
Omega Ace made quite a stir when he was released, but hasn't proven too popular in the long run despite having solid stats and a good ability. Given Push the Limit, it's not too difficult to get the Focus token and Target Lock that he needs to change all of his attack dice to critical hits. While this is best when you're hitting hull, it's useful against any target as it means that none of your dice will miss.
Zeta Leader, also known as "High Roller," is my personal favorite TIE/FO pilot, and is becoming one of my favorite pilots in the game. With PS 7, an EPT, and the ability to add an extra attack die at the cost of taking a Stress, he hits hard for a budget price. My favorite EPT for him is Wired; since he'll almost always be stressed when attacking, it allows him some re-rolls for just 1 point. TIE MK 2 engines are also a decent upgrade as they open up his dial a bit once he starts attacking. Any of the current Tech upgrades are decent for him, but I prefer Comms Relay if I have the points just to keep him alive and fighting.
Despite my love of Zeta Leader, it's clear that Omega Leader is the accepted strongest TIE/FO pilot. Also known as "Lockdown," Omega Leader combines excellent PS with a great ability. Any ship that Omega Leader has target locked cannot modify dice when attacking Omega Leader or defending against her attacks. This is an amazing endgame ability, and Omega Leader has a good chance of defeating any other ship one on one. Her ability is less useful the more enemy ships there are, so you'll often want to keep her out of the line of fire until you can get her in a position where you oly need to confront one enemy. The standard loadout on her is Juke and Comms Relay, and I can't really argue with that. It allows her to modify her target's defense (which the target then cannot fix) as well as maintaining good defense against her target's unmodified attacks. While none of the TIE/FO pilots are weak choices, Omega Leader is widely considered one of the best Imperial pilots in the game, point for point.