I own both the FH3 and the Aria, so I can give a small comparison.
Packaging/Accessories: Both the FH3 and Aria come in a nice Box with everything well stored. They are the type that you fold open (the front functioning like a lid). As for Accessoires, the Aria comes with a couple of standard silicon tips and a small circular carrying/storage case that can be closed and opened with a zip tie. Others said it‘s too small, but I have never had any problems storing them in there. The FH3 on the other hand comes with a wide variety of tips (Balanced, Clarity and Bass silicon tips - each in three sizes - as well as foam tips), a soft carrying pouch as well as a solid case.
1:0 for the FH3 on Accessoires
Build Quality: Both the FH3 and Aria have a Metal shell that‘s not too heavy and feels very sturdy. The FH3 has a matte black coating and a wave-like structure on its back that looks and feels nice. The Aria has a matte black coating as well, with gold accents on the faceplate. Both have a Metal nozzle without a lip. The Connectors feel sturdy; unless you swap cables daily or do not use excessive force, it is unlikely that they will break. The Aria uses a standard recessed 2-pin connector while the FH3 uses MMCX.
2:1 - Draw
Cable: The Aria uses a black, nylon braided cable that has minimal microphonics, but feels light and sturdy. It has no real form memory and does not tangle easily. The FH3 cable is a silver coated one. It‘s soft to the touch and has a nice weight to it, but does not weight you down. It feels sturdy as well. Both cables should not break easily.
3:2 - Draw
Fit and Comfort: Both the FH3 and Aria have a shape that is ergonomic to my ears and fits well into them. I can wear both for multiple hours. After 4 to 5, a bit of fatigue and discomfort sets in on both, but nothing major. I use Final E Type Tips on the FH3, and SpinFit CP145 on the Aria.
4:3 - Draw
Sound: I consider both the Aria and FH3 to be great IEMs in their respective price bracket purely for sound. They provide different Flavors and Strenghts.
The FH3 is a more V-Shaped sound while the Aria is harman-tuned (Moondrops has it‘s own harman-like house sound). The Aria has a neutral-warm sound profile that is very smooth. The Midrange sounds full and slightly forward, with Bass being slightly boomy, but neither too much nor too little for my taste. Bass is there and has a nice texture to it, but Bassheads might crave for more. Treble is there and extended, although it could use some fore air. It is however never fatiguing as a result.
The FH3 has a slightly dip in the lower mids while having a slight rise in the upper mids. Female vocal can sometimes sound a bit shouty, while male ones can sound a bit too far away. Bass is really the strenght of the FH3. It is fast and snappy with good impact while being a bit soft in nature. It‘s like being hit very hard with a soft pillow. Treble is adequately extended with slight sibilance from time to time.
The Aria beats the FH3 in coherency big time. Everything sounds connected and noir of one form while still providing decent separation and detail retrieval, especially for the price. The FH3 in comparison sounds incoherent and also exposes a bit of a metallic timbre.
The FH3 has better separation and imaging in comparison. It is also a bit more resolving as a whole.
The stage sounds a bit wider on the Aria, while the FH3 sounds bigger in height.
I would describe the Aria as a smooth, pleasant listen that can do every genre at lest good.
The FH3 is a more energetic, „fun“ listen that struggles a bit with some vocal-centric tracks.
I would personally take the Aria over the FH3. They are both great IEMs, but the Allrounder qualities of the Aria make it the better set imo.
Some great genres for each set:
Aria: JPop, KPop, vocal tracks, acoustic, Jazz, RnB, Rock
FH3: HipHop, Metal, Rock, Electro