How to start...here are my two hours listening impressions with the FA1.
I'm really loving what I hearing so far! they are exactly as some users have described in this thread, definitely! they are well balanced, warm, excellent mids, non-fatiguing, extended treble, and good details retrieval.
Actually, I would say they are like an "HD 600" in form of IEMs but a bit warmer and with a slightly less kick in the bass as someone told me above; I do not discard this might improve with burn-in. Although, about the kick in the bass, this is also very track dependent. For example, listening to Angel Olsen "My Woman" album, there were tracks where the kick in the bass felt a bit more pronounced than others track within the same album.
The vocals and mids in general.... this is a winner for me, I prefer them over the FH5. Just one track from Angel Olsen.. "Sister"; the guitars, the vocals crescendo, textures of the guitar solo, all sounded great and way more satisfying to me than listening to it from the FH5.
Soundstage, not too much difference here. Take it a grain of salt, but I would say the FA1 sounds a bit wider and has slightly better height, but the FH5 has just a bit more depth.
Comfort wise..... quite superior to me than my FH5, a good improvement with the seal, isolation, and comfort.
These are my impression, for now. No tips rolling yet, using default cable, paired with just my iTouch 8th gen. I will give more impression later with other sources, tips, and cables. They sound GREAT with Jazz, rock music, pop, acoustic.