The QT5 by RevoNext are quite popular by now, and for a good reason. These earphones combine everything you would wish from any expensive pair: great build quality, high level of comfort and, most importantly, exceptional audio quality. Except that the QT5 are not expensive at all. For a surprisingly low price and relatively modest specs - only a single dynamic driver paired with a single balanced armature - you get just about all of the mentioned goodies.
Sure, these earphones aren't perfect, but their sound is about as exceptional as the twice-as-expensive QT2/QT2S. I would go as far as saying that the drivers in the QT5 are the same as the ones used in QT2/QT2S, or at least partially the same (minus a second dynamic driver). If I'm wrong, then they are at least tuned very similarly. One particular difference I will mention is while the QT2/QT2S emphasize the mid-bass a little bit more, while the QT5 seem to emphasize sub-bass while having relatively calmer mid-bass, but this might have more to do with the difference in fit rather than tuning. The timbre is very similar between those earphones.
All in all, the QT5 are one of the best pair of earphones you can get in that price range. I wouldn't skip this one, especially if you don't already have the QT2/QT2S.
With the included tips, I could get pretty decent seal, but had to insert them deeper sometimes as the nozzles are quite stubby (wide and short) so a good grip is necessary. Other than that, the earphones are quite comfortable. No sharp edges to complain about and no discomfort other than the mild pressure from the stubby nozzles. I preferred to swap the ear tips with a pair more suitable for my ears, but that might no be an issue for your ears at all.
Lows / Bass
Very extended and deep bass reproduction. The mid-bass is more moderate, compared to QT2/QT2S, and yet the sub-bass remains powerful and delivers a very fun listening experience, especially with folk/punk rock and electronic dance music. The bass never distorted on me, even on higher volumes, and never muffled or muddied the mids. Definitely impressive drivers are used in there.
Mids / Vocals
Given the extremely similar mids to the QT2/QT2S, I'll just repeat my thoughts: The mids are just dreamy! They are not recessed at all, like on many other earphones of a similar setup, but are also not edgy, which is a common issue with a huge portion of earphones, especially those with a hybrid setup. The perceptional distance of voices and instruments from yourself is phenomenal. You will feel surrounded with sounds and will also be able to tell the direction from which the sounds originate. Not only that, the mids also sound extremely natural without any coloration, at least as far as I can hear. Those mids are as universal as it gets!
Highs / Treble
Like the mids, the treble is very similar to QT2/QT2S, hence I repeat: Very detailed, crisp and sharp, but not fatiguing. Obviously, certain tracks (specifically under the electronic music umbrella) will still cause some pierce and it seems inevitable when it comes to bright earphones, especially those with balanced armatures located in the nozzles. However, those are some of the most extended and accurate-sounding highs I've ever heard so far. Certainly, you will get more sparkle with the extremely-extended treble of ZS6, but QT2's highs will not tire you. Compared to the similar TRN V20, QT2's treble is more accurate and detailed, less rolled-off but instances of pierce are far less likely to occur - and that what makes them truly worth their extra price.