Well, there are actually two units in the list. But I know what you mean.
If you have two virtually identical (high cost, AD, stealth, high DEF, low ARM) units, the second unit probably can't be deployed optimally because the first unit already takes that spot. SotR is all about deployment. Second, in order to get the free MHA solo, I would have to drop Griffon and A&H. You are shooting yourself in the foot in the current incorporeal meta, if you don't take A&H to every list (Thyron doesn't need them but that's another discussion). Third, Garryth sucks at buffing units. Miraged MHSF can be OK in certain situations, but usually that spell isn't worth the focus.
Garryth battlegroup The minimum battlegroup with support models (all other jacks need focus to do their job), so that Garryth can concentrate on staying alive and killing enemies. Cheap light jacks can be sent to contest zones when needed.
Elara1 battlegroup Elara1 has the best battlegroup spell in the faction and her jacks doesn't deplete Garryth's focus pool, so it makes sense to assign all damage dealing jacks to her battlegroup. Daemon is probably the best area denial piece in the faction. If enemy isn't careful, it will eat units, wreck light jack formations and autohit* enemy warcasters with boosted pow12 during feat turn. I'm not 100% convinced that Griffon is the right 2nd jack for Elara1. Speed of Death is great for reach models, but then again the Daemon-Gorgon or Daemon-Daemon module is worth testing out.
* You still have to hit that nearby heavy with boosted RAT5.
Warcaster attachment Madelyn increases the area in which your warcaster can be deployed by making the warcaster untargetable by warrior model melee attacks ("area denial booster"). While this isn’t the most useful ability in every matchup, it can win the game if your warcaster is fast killer like Garryth. If enemy doesn’t have melee warrior models, Sucker! and DEF14 make her a good solo to hold flags and contest zones.
Mage Hunter Solos The real power of the theme (and faction as a whole) is our excellent combat (and support) solos. The theme amps up their power by adding RFP and tough bypass to melee attacks. My general game plan revolves around protecting and maximizing the damage output of these elite killers. If I have to sacrifice warjack or use a feat to get another round of decapitation attacks, I won’t hesitate. In my opinion, AD and 14” (or 10,5” in case of Narn) melee threat range is a trap. You should be charging models that are close to your lines so that enemy can’t kill your valuable solos.
MHSF+E3+Soulless escort MHSF+E3+Soulless escort the most expensive unit the game. Luckily for us, it’s also one of the strongest if you play it right. Because it’s so expensive, the unit should never engage an enemy that can seriously threaten it. Flank deployment, AD, Stealth, pathfinder, RNG12 guns, repo 3” and some Gallows help from G-man should be enough for most foes. Buy 12” and 3” measurement sticks and learn to make quick activations.
Lady Aiyana and her loyal pet Like I stated previously, I think that A&H is a mandatory unit in a competive list. The unit is also surprisingly accurate (2xRAT8 shots) and hard hitting (2xPOW14) for its point cost. For example a minimum unit of Nyss Hunters have similar ranged accuracy and damage output, but cost 4 points more. Playing G-man While Garryth isn’t the most hard-hitting model in the faction, he is one of the most durable. Stealth, pathfinder, DEF17, kd immunity, acrobatics makes him very difficult to kill. There are only few problems in the game that can’t be escaped by 14” side move, which is always available because SR2017 doesn't have sideline killbox. Arc noded double boosted or double gallows should be Garryths primary attack mode. Gallows pulled models are focus fired by repo MHSF and SoD buffed jacks and Elara1. If no targets present itself, Garryth camps everything and moves to a better position. Mage hunter solos are kept safe and are ready to engage anyone foolish to come too close.