Okay, the UE 4000s have arrived. I haven't listened for very long, but I'd like to give my initial impressions. Disclaimer: I have probably been spoiled in the past with SRH840s, and also probably forgotten just how bad $5 Deal Extreme IEMs are. :)
I really like the comfort, and they feel well-built without being ridiculously heavy. Israel is a pretty hot country, but I've been able to walk around outside for 20 minutes without sweaty-ear syndrome.
Sound-wise, I've been a little bit underwhelmed. So far we've had Signals by Rush, and the first Velvet Revolver album. At first I was really disappointed, bad artefacts etc... Then I cleared the cache on Google Play Music (Android) and set streaming quality to High (Normal is the default). They sound... fine. I mean, not offensive or anything, but not really making me go wow. A little muffled / veiled / fake perhaps. I'm not sure if this is the bass punching too hard, or just a lack of clarity at the top end, I find it hard to describe sound with words. I checked my phone a few times to make sure there were no EQ or sound processing involved.
To be fair, for $20 plus shipping (yes I went purple), they are great. I need to keep my perspective and remember I was on a budget this time. But I'm keen for the UE 6000s to arrive, to see how they compare. Plus of course, I might appreciate the 4000 sound signature more over time. I will also say that being comfortable on the veiled side, means that I should have no problem to listen for a long time without fatigue.
I've used the mic as well on a phone call - nice bonus. Sadly the volume buttons don't work with my Moto G, but that doesn't bother me.
So thanks for the recommendations, and I'll report back when the 6000s come. :)
PS I don't recommend the purple, it's brighter than it looks in the pictures. ;)