The Cyber-Harpy is a fairly extensive body modification. The human host is stripped down to a head and torso and are grafted into the harpy chassis, which has shock absorbing digigrade legs and feet, back mounted wings, a mini power cell and an a-pod. Some versions allow the host to keep their arms and hands, some offer secondary robot limbs for close use and fine manipulation, some simply have the jointed wings as the only manipulators. Harpy mods are not known for being major tool users for this reason. Keeping arms and legs can be done, but it is generally discouraged because these are considered soft and pain vulnerable liabilities to the rest of the cybernetic package. They do retain a humanoid shape and posture, they are not bird shaped cyborgs.
A cyber-harpy can fly quite quickly, using their a-pod, lift from their wings, and some have the option to mount special equipment to make them faster. Rocket pods and thust packs are not uncommon. For full metal harpies, this gives them the ability to go into hard vacuum without a suit or gear, and retain their mobility. This is one of the most common reasons that there are cyber-harpies, space work and rescue ops. For specific missions, these harpies can carry supplies, or even a person in a space hardsuit to where they need to be quicker than a shuttle (at close range).
The advantages of the harpy configuration is that they are better and more agile fliers than jetpack power armors or other personal flight mobility options, and smaller than any non-drone flight vehicle. A harpy can catch people who have fallen from extreme heights, rescue people who have come untethered in space, and generally do aerial versions of parkour.
The most complicated things about a harpy build are lacing the human host into the chassis, and the construction of the wings. Navy planes have wings that fold or pivot in one place, sometimes two. A harpy's wing might have a dozen joints in it, allowing for the wings, which can be as wide as 35 feet, to fold up into a human sized space. These are highly reliant on smart materials, like reflexokinetic fabric, pliable at normal state, but rigid when an electric current is pulsed through it. The wings also use myomers, synthetic muscle, rather than actuators or servos. The same electric charges that keep the wing material stiff control the shape and angle of the wings. The harpy does and factually uses it's wings as flight control surfaces. The a-pod lets them float, but it is a mass offsetting aid more than it is a flight device.
While the number of harpies is low, they have been around for a while, and appeal to people who want to fly on their own, or feel connections with avians more than they fellow humans. They are commonly found on aerostats, large civilian airships, especially large space stations, the O'Neal cylinder type that are hollow and the inside is covered with farming communities, and the upper sections of mega structures.
Harpy vs Angel - there is an ongoing debate between angel biomodification augments and harpies over who is the more legitimate heir of the air. Both have the ability to fly, and while harpies are much better at flying and have fewer augmentation issues, the 'angels' are entirely biological, and like to present themselves as superior, even when their augmentations are purely cosmetic.
In contrast with many other extreme mods, there are several companies that make harpy cybernetics, and have ironed most of the kinks out, meaning that they are not affected by the quirks and problems associated with scratch and single build extreme cybernetics.
The military has made use of harpies in some situations, as their mobility is impressive, and a harpy can fly without their a-pod being powered up, giving them a very small EM signature. This has fallen out of favor as drones are cheaper and more expendable.
Shadow-ops LOVE harpies. A human operator, a human voice and touch, the ability to fly without relying on rockets, thrusters, or another vehicle, the ability to carry special tools, or exotic weapons. Mercs and intel agencies make as much use of harpies as they can, and always want more. There are generally just not that many people who are hot and bothered to have their arms and legs cut off and be stitched into mechanical bird body. (not actually a bird body)
The Raven's Wing - a group of shadow ops mercenaries, the Raven's Wing is a night ops squadron that uses their ability to fly for recon, extraction, and destruction missions. They can enter airspace largely unnoticed, use surveillance gear, or do land and grab missions where they literally snatch people or things off of the ground. This can be borderline kidnapping, or extracting members of another group out of a bad place. Their favorite destruction tactic is to drop incendiary devices and ride the thermals generated by the resulting fires.
The Blood Wings - a more chaotic mercenary group, the blood wings actually specialize in assault and close quarters combat. While their wings are still vulnerable to being damaged, the blood wings rely on softening their targets before hitting in close, especially using needler rifles, needle grenades, and then wading in with their light hyperedge swords and progressive stilettos. The end result is a decimated position that wasn't expecting the attack to come from directly above them, and a bunch of blood covered harpy cyborgs.
The Ghost Wings - Ghost Wings are an elite classified all but unknown cadre of intelligence operatives who work for a government that doesn't acknowledge their existence. The Ghost Wings have added stealth and optical cloaking devices, allowing them to be both small and invisible. They work alone or in pairs, and do the unspeakable dirty work and false flag operations of their unclaiming government. The truth of being Ghost Wing isn't that they kill terrorists or villains, but that they commit acts of terrorism and villainy against their own people for the purpose of swaying public and government opinions.