Below are sound impressions of the Nicehck EB2 and comparisons to the Monk Espresso and QianYun Qian 69 from a review I did for Head-Fi a few months ago:
The Nicehck EB2 has a restrained and clear audiophile-friendly tuning. Sub-bass extension is poor. Mid-bass is lean but well-articulated. Bass transients are quick but bass texture is one-note. Mid-bass bleeds slightly into the lower mids. The lower mids are gently recessed. Male vocals are clear but could use more warmth. Upper-mids are emphasized, conveying excellent presence but a little too much bite. The emphasis on the upper mids combined with the lean bass can make the EB2 sound thin. Treble is mildly veiled, extended while not prominent. Detail resolution is excellent but I had to strain my ears to pick it out. Instrument separation is not great, especially at higher volumes.
Nicehck EB2 vs QianYun Qian69
The Qian69 is more V-shaped. The Qian69 has better sub-bass extension. Bass dynamics are similar, though the Qian69 has more textured bass. The EB2 has less recessed mids. The Qian69 has more prominent treble and sounds airier. The treble on the Qian69 is more fatiguing. The Qian69 has a larger soundstage and slightly better instrument separation. The Qian69 is easier to drive from a smartphone but does not noticeably scale with better amplification.
The Nicehck EB2 benefits from dedicated amplification, which improves instrument separation and makes the treble less veiled. The difference is distinct but not night and day.
Nicehck EB2 vs Monk Espresso
The Monk Espresso is warmer, with slightly better sub-bass extension and more mid-bass. The EB2 has better bass articulation, with faster attack and decay. Mids on the Espresso are more recessed than on the EB2. Lower treble stands out more on the Espresso. The EB2 has a slightly bigger soundstage. Instrument separation is slightly better on the Monk Espresso. Both scale with dedicated amplification.
I like the Qian69 the most out of the three. It has the most engaging sound by far.
I also find it interesting that generally I hear a much bigger difference with dedicated amplification using earbuds than with IEMs, which I assume has something to do with the high impedance ratings of the EB2 and Monk Espresso.