I started to read through the first few pages and noticed a lot of interest in comparison of FiiO EM3 ($10) to VE Monk ($5), so figured to jump in with a short write up.
Earbuds were never my cup of tea due to my ear anatomy. My concha area, right outside of earcanal opening, is rather small so I can't fit well earbuds which means not being able to have a proper evaluation of low end impact. So I typically go for a naked fit, without those sponge foamies/donuts. The generic shell, such as the one used in Monk, is really at the threshold of comfort but I can still tolerate it, and as a matter of fact with a new ZEN 2.0 and updated shell I can fit it better. FiiO's EM3 is even smaller in comparison - this one fits perfectly. Overall EM3 design is slicker, more original, unlike Monk which is more generic. Also, addition of universal single button in-line mic is a plus for smartphone control and playback control with some FiiO DAPs. I also like L-shaped headphone jack better. Overall, in terms of external design I will give more credit to EM3, which also justifies the price difference.
When it comes to sound, I found Monk to be more transparent, with a clean, open, and more expanded sound, noticeable improvement in width and depth which I found to be above average in comparison to EM3. I'm getting less sub-bass (unless I push earbuds in with my fingers), but still a fast punchy mid-bass without any spillage into lower mids, lower mids are leaner, and upper mids are clear and smooth with a good natural delivery of vocals, treble is also clear with a little more sparkle, crispier definition, and slightly more airiness
With EM3 the sound is more intimate and soundstage is just average, while tonality is warmer, and sound is thicker. I'm hearing deeper sub-bass and more bass impact due to smaller earbuds that fit better in my ears. But I also hear a bit of spillage into lower mids that have fuller body, which along with more bass make sound a little more congested and a bit muddy, though it could be fixed with EQ. Upper mids are clear, smooth, with a good organic delivery of vocals, treble is clear and well defined, but not as extended and not with too much airiness.
Based on my personal sound preference, Monk hits closer to home for me, though I wish for the best of both worlds by combining EM3 design with Monk driver/tuning.
For comparison, here are some pictures (click to expand):