I believe she's well rounded in offense and defense. Not only does she have the Uranus System, Hephaestus , and the Apollon Bow she can also fire small homing explosive energy blasts from her wings.
This is a full picture of Ikaros.

She's not that strong in CQC, and is more of a ranged fighter/ strategist. She can survive explosions if I recall, so I think even without the Aegis Shield she can survive a beating.
As for what she is... here is a description:
The Angeloids (Angel and Android) are a series of androids built by Synapse. As part of their name implies, they are modeled after Angels and are programmed to serve their masters. They select their masters through the process called Imprinting. The first generation of Angeloids (Ikaros, Nymph, the Harpies, and Astraea) were built by Daedalus, while the second generation of Angeloids (Chaos, Hiyori, Siren, and the Melan) were built (or in Hiyori's case, turned into) by the Master of Synapse. Each Angeloid has a letter from the Greek alphabet, which descends for every new Angeloid built. Ikaros, the first Angeloid built, is a "Type Alpha" Angeloid, while Ikaros Melan, the most recent Angeloid, is a "Type Theta" Angeloid.
Every Angeloid has their own unique abilities and powers, which are determined by three factors:
Emotional Control
Battle Capability
Processing Capability
For example, Nymph has high emotional control, processing capability, but has low battle capability, while Ikaros, on the other hand, has high battle and processing capabilities and low emotional control. The Angeloid's names, weapons, and abilities originate from Greek gods, mythological figures, or, in Chaos's case, words that stem from Greek roots.
Despite being androids they are shown to have relatively soft, and human like skin. Capable of feeling pain and such. They also have incredible stamina.
Now... another Angeloid that would be interesting to see John fight would be Astrea:

Spoiler
Astraea was originally created for combat, coming equipped with the lethal, overpowered photon sword "Chrysaor", which can cut through almost any material in the world and crackles with raw, untamed power when in use. She also comes armed with the special Aegis L Shield, which can block any frontal attack upon her and make fighting her in face to face combat a nightmare. Combined with her blazing speeds that she can achieve with her powerful wings, Astraea is one formidable opponent in battle that should not be taken lightly. However, there are several key flaws that she suffers from that keeps her from being the most feared Angeloid in Synapse. First, the downside to her powerful shield defense is that it leaves her sides vulnerable to attack and it drains a incredible amount of energy to maintain it for long periods of time, so she is limited in her use of it in battle. The reach of the majority of her attacks with Chrysaor is somewhat limited as well, and it can leave her open to attack if she misses a slash at her opponents. Unfortunately, in what is her biggest flaw and the primary reason that she will never be a dominant Angeloid in Synapse is that as a trade-off for her jaw-dropping levels of strength, combat abilities, and high emotional control, her brain-processing power is extremely low in comparison, often resulting in Astraea suffering major klutz moments and the eventual failure of her assigned missions due to her excessive blunders. In addition, her low processing levels often result in her easily falling victim to many of Tomoki's perverted schemes regarding her massive breasts, and it also leads to her doing some absolutely bizarre things that she considers "normal", while everyone else is blown away at just how stupid she is behaving in their presence.
It is not currently known if Astraea was equipped with the advanced PANDORA unit like fellow Angeloids Ikaros or Nymph had installed within their systems. Current speculation suggests that her creator Daedalus might have installed it within Astraea, but it has yet to activate as seen in both Nymph and Ikaros.Astraea is more dangerous in CQC, but not ranged combat. I think she would be a decent, and more fair match for John despite her weaponry and such... but her stupidity would definitely hinder her in a battle.
Good thing Astraea, and Ikaros are both good.
Just imagine if either one of them were in the RP and Imprinted on John, thus making John their master...