Well, I'm using a pair of Zero Audio Duoza that go for around $110 (they don't sell them officially outside Japan, but there are plenty of good e-bay re sellers) and so far I've not found anything around $100-150 that comes even close in terms of overall sound quality. In fact I've seen people comparing them favorably to Audio-Technica ATH-CKR10, which go for ~$200. You can find reviews on head-fi if you're interested.
2 dynamic drivers / ear and, similar to the edc3, they are designed with a fairly neutral sound signature. What I absolutely love about them is their clarity and their superb response to equalizer changes. They aren't bass-heavy by default, but goddamn can you pump it up if you want to (which I do) without distortion. Though I'd say it's not really worth dropping ~$100 on the Duozas if you don't have a very good source (both DAC and files) to make them shine, there are cheaper options.
Using 320kb/s mp3 there's not much of a difference between the Duozas and Zero Audio's Carbo Basso (~$40). A bit more clarity and a wider soundstage. That's not criticism for the Duozas, though, it's more like very high praise for the Carbo Basso, which can pretty much make the most out of mp3 audio.
Using uncompressed FLAC files, there's a huge difference in detail, clarity and soundstage. It's like listening to the same song with extra instruments. You can hear every reverberation of a guitar string, you can clearly hear every single instrument, beautifully separated within the music. And they don't compromise, either - lows mids and highs are all just as good. And they're so responsive to EQ they can be tuned for pretty much any preference.
In fact, for that reason, I'd say if you only listen to mp3 or streamed music like Google Play music (which has 320kb/s files), it's not really worth dropping more than ~50 for a pair of plain headphones (I was ok with $60 for the original EDC because of the extra accessories and removable cable. The Carbo Basso are better in every way in terms of sound quality. Alas, I lost mine)
I'd love to hear how the EDC3 compare to the Duoza. If they come anywhere close, I'd grab a pair for the removable cable and better fit in my ear (I'm assuming they will be very similar to the EDCs). If there's complaint I have over the Duozas, it's their flimsy cable (though I've used mine for over 2 years with no sign of fatigue) and not-so-great fit in my ears. They tend to slip out if I'm moving vigorously. I really like how the EDCs fit my ear and I'm much more comfortable using them while biking or doing anything "active".
I'm curious if Massdrop will ever have Zero Audio drops. I'd be first in line, those people make fantastic IEMs for the cost.