Ok let me be the bad guy to convince you to Xelento, as I have heard or auditioned most of them...
Sound signature wise, I describe Xelento as a bassy IEM - think of IE800, but instead of mid-bass heavy, Xelento is sub-bass heavy. Also without the bright treble of IE800 - Xelento sound incredibly smooth and cohesive from 200Hz all the way up.
Sound quality wise, Xelento is up there with the biggest boys. If you want to compare it to:
SE535 - 535 has midmrange and nothing but the midrange. Muddy across the frequency range compared to any true flagship IEM.
W60 - to me it's the worst ~1000 option out there. Just muddy and congested. Like a SE535 with a tad more bass.
IE800 - I am a huge Senn fan, but IE800 is a failure. Muddy, but not as bad as the W60 mostly due to IE800's semi-open nature. The piercing treble is the worst probably out of any IEM I've heard - think of Apple Earpods' boosted low quality treble, but worse.
Roxanne - Now we are entering the "big boy" territory. Roxanne is a SE846/W60 on steroid - huge soundstage, more layered subbass, more open midrange, and most importantly a lot less muddy and congested. The renowned midrange of SE846/W60 is just loud in comparison. They have no articulation whatsoever compared to the Roxanne. Still not enough treble to be neutral or airy to me.
Layla II - Roxanne with slightly more treble and even more sophisticated midrange. Still not enough treble to be neutral or airy to me.
Xelento - Now we are entering the "biggest" boy territory
- More treble quantity, finally bringing enough "air" to the music. Not necessarily better quality, as Layla is one of the most "precise" IEM out there.
- Larger soundstage than the Layla. Yes I said it. That's what I have heard before selling my Layla. I couldn't believe it myself.
- Less midrange quantity than the Layla, but more realistic timber and decay - reminds me of a HD800S being compared to a HE1000. Dynamic drivers always have an edge. May be a personal preference thing.
- More open. I hate to say it, but Layla still sound a tad congested compared to Xelento. To me this is the most important aspect about SQ.
Other biggest boys (some I'd say better than Xelento in terms of SQ) include UM Mentor/Mason, KSE1500, VE6/8. I decided on Xelento as a combination of good (enough, not best) SQ and preferred sound signature.
Overall I think it is most fair to compare Xelento to Sony Z5 or JVC 1200 or IE800 or even an Apple Earpod than to compare it to W60/SE846-type sound. If you like the Sound signature of W60/SE846, look to upgrade for something like Layla, A12, UM Mason, etc. But if you want to compare in terms of purely sound quality, they are no match for Xelento.