I just got my sample today from Kiwi Ears website (2 weeks time and this time no local taxes)...
Redcarmoose convinced me to give at least a try with his complete review
https://www.head-fi.org/showcase/kiwiears-quintet.26582/reviews#review-31155
I really wanted to give a try to a rather complex and risky/muddy hybrid multi drivers like this, though I think the best results for me were mainly none hybrid systems (except IER-Z1R absolute reference, XBA-N3 as fun reference & EXT quite good even if far too expensive and weak), but, till now I enjoyed clearly a lot single DD (IE900-600, Xelento & HA-FW1800), the surprising Planar (ZeTian Wu) and for a month, I got my new tone reference IER-M9 with some full load of "Sony"'s special BA drivers.
My first feeling after a pair of hours with the Kiwi Ears Quintet, is that I am a bit surprised that mid high and high frequencies are clearly less detailed than with my IER-M9 or IE600, as I was expecting something "different" even aggressive with some BA + micro Planar Magnetic + Piezzo Bone Conductor involved in the sound ...
Compared to the M9, it seems some cymbals are muffled a bit in the path for some of my jazz test tracks..
For ultra low and low frequencies, in my case, everything seem to be there with the DD, deep low frequencies and good impacts (better than IEM-M9 without EQ).
Basically, I am one who is not really convinced by any hardware burning, cables & amp effects on sound quality, though FIIO pure silver balanced cable seems sometimes to improve high frequencies for my ears (this can still be a placebo effect).
Usually, I am far more convinced by some proper EQ and of course ear tips effects..
So, even if some of the Kiwi Ears stock ear tips inclued in the box are really comfortable, I felt some of my other ear tips with very large hole nozzle => opens the sound by a significant margin in mid-high/high frequencies.
So, I am thinking the Kiwi Ears Quintet fits perfectly in my ears as they are long and rather slim (this should allow to lay down with the head on the side ), In my case, they are :
-> totally non fatiguing for hours with no sibilance at all,
-> with a rather "dark" tone signature,
-> giving quite promising impacts and not too muddy low frequencies.
I will still take some time to "burn" a bit this quintet (?) and mainly my ears and I will see in a week or two if they will really join my actual dream team : Ier-M9, XBA-N3, HA-FW1800, Ze Tian Wu or go on the shelf full of unused IEMs and dust...