Posting this short comparison here by request of Mimouille... I haven't been on the tour and only had an hour or so to try the Vision Ears 2, 3 and 4, but it was in ideal quiet surroundings and I had my UERM to compare, so I'm reasonably sure of my findings.
- All of these are technically very impressive.
- Driver integration is among the best I've heard from multi-BAs.
- VE2 are the flattest of the bunch, most similar to my UERM and just a little north of neutral in (deep) bass.
- VE3 are slightly mid-centric with a moderate mid/upper bass emphasis and noticeable lower mids warmth.
- VE4 are slightly U-shaped with enhanced deep bass and treble, but less mid-bassy and warm than the VE3.
- Resolution and refinement improves a bit with the number of drivers, but differences are rather minor in my book.
- Soundstage is quite good for closed IEMs, the VE3 sounding a tad more intimate than the others (due to highest mids presence).
Overall I was very pleased with all of them and they outshone the Stage Divers 2 and 3 (which I also auditioned) with their slightly less dry and more refined performance. The VE2, however, were an unexpected surprise and the stars of the show for me, falling just a little bit short of my UERM's refinement and finesse, but being pretty much at eye level with them in most other aspects. Easily the best dual driver BAs I've heard so far (though probably also the most expensive).
I'm very tempted to purchase the VE2, because the sound quality difference between them and the UERM is rather small and they offer only a tad more bass, which would pretty much match my ideal sound signature for mobile use. Just holding off for now, 'cause I've been offered to demo the new JHA Roxanne, which might or might not hit my wallet in an unpredictable way, lol.