NOTE: This was originally meant for this thread, but I don't think its active anymore so I'll just post it here.
Alright guys here is my honest opinions of all the budget and Chi-fi IEMs I have used, and I have a feeling that many will disagree:
Rock Zircons - Bleh! I don't know why everyone loves these. I love love love the design but hate hate hate the sound. The sub-bass is way too congested, with little breathing room for the mid-bass. Because of this the bass feels very one-dimensional and not at all dynamic. There's also sibilance in the high-mids to low-highs with the upper highs rolled off, making it one of the most artificial highs I've ever heard. Soundstage is also unimpressive with no sense of spatiality.
KZ ED9 - One of the best IEMs I've ever had. Huge massive soundstage that makes everything sound so immersive and 3D. Excellent treble extension with micro-detailed highs. The bass, although relatively quiet, has some very good dynamics to it.
KZ ATR - Again, bleh. Bass in general is pretty minimal and sub-bass is pretty much nonexistent. Treble is rolled off yet harsh. Has a very dark tonality to it which I dislike.
KZ ATE-S - The ATE-S sounds much more superior to the ATR in every way. Better bass extension, super detailed mids, and a more pronounced treble but still in a darkish tone.
UiiSii HM7 - Not my cup of tea. Highs are a bit too exciting and sharp making it sound very sibilant and piercing no matter how I EQ it. Overall not much resolution at all.
Plextone 41M- Again not my cup of tea either. Like the Zircons, the sub-bass is WAY too loud and congested and eats up the mid-bass making the bass sound one-dimensional. Mids are pretty good. The treble is so sharp and piercing that it pretty much feels like everything is screaming at you.
If I were to pick any of the above to be my daily drivers, it would definitely be the ED9 and the ATE-S. Zircons... maybe.