Pros: build quality, price, low microphonics, decent clarity
Cons: unrefined bass, grainy mids, average highs, driver flex, average instrument separation
Now let me start by saying that at the time I purchased these Delta's, I was looking for a step up to my Philips SHE3580's to get a better quality budget iem. I have just sold my JVC FX40's and my Sennheiser CX215. This before I bought the Vsonic VSD1S, GR99, or the LG Quadbeats. i was researching through head-fi for a budget bump in quality. The Delta's were getting a bit of positive press, so for $20.00, I took the dive. I was excited to receive my newest go to IEM. When i go them in the mail, I hurried home and did the mandatory 2 hour burn in with sweeps and noise at moderate levels before listening to them. Then I popped them in using my Sansa Fuze and E11 amp, and well...ummm....what's up with this "balanced bass"?? it was muddy and forward. The highs were nicely presented, but the mids were grainy and instrument separation was less than the SHE3580's. Ok so maybe they need some decent burn in time? I put a loop on my computer with the E11 amp, playing SKREAM! A few hours later i took them off the burn loop, and put them in again. This time I switched between the Sansa, my Sony 475, and iPod Touch. Though clarity improved and the highs were fairly refined and extended, the bass was still very unruly and unrefined. The grain in the mids was still present, taking away from the smoothness of the presentation, and the reported balance just wasn't there. These turned out to be bass forward/mid forward IEM's, where the bass simply wasn't refined enough to pull off a high end budget presentation like the SHE3580's or the LG Quadbeats. Even the JVC FX40's had better instrument separation and clearer mids than the Deltas. The biggest problem i was was that I had to turn the bass EQ down to get decent clarity, and flat, the grain in the mids really shown as these struggled to present instrument separation with average soundstage and definitely budget imaging. Even the GR99's excelled over the Brainwavz Delta's in these categories. Then there's the question of the mild but still noticeable driver flex from the shape of the aluminum housings. They are very small, and lightweight, and as such, with the design of the driver housing, driver flex tends to happen from the seal being moved within the ear canal from the housing construct. These are most definitely a $20.00 IEM, and no, IMHO they do not perform outside and above their price range. They perform right at the price they fetch. There are many budget IEM's that perform better and brighter at the price range, and exceed their domain. Several are mentioned above.
Now build quality is definitely a plus. These things are pretty, built like a tank, and the high quality cord is free of most microphonics and tangling. They also have a nice angled jack, and lovely strain relief. Gorgeous design...and BUDGET sound.