The thing I've learned is that headphones and IEMs can sound completely different to different people, just because of differences in the shape of your ears and ear canal.

I bought some custom IEMs and had the opportunity to test ~10 of the super high-end options from several different brands. I found that there was no correlation whatsoever between price or even brand and how good they sounded to me. The technician I was working with said he observed the same thing all the time in the professionals he worked with. He'd have musicians on the same instruments in the same roles in the same group come in and all walk put with completely different products.

IEMs are the most personal but even headphones have the problem.

Because of this, my recommendation is that you make purchasing decisions in one of two ways:

- Learn how to EQ to get a sound you like. Purchase based on objective measurements like frequency response curves to find products that require minimal EQ to match your preference.

- Only buy after listening, or buy, listen and return if that's an option for you.

I recommend avoiding purchases based on reviews that make subjective judgements about the sound.

If you want to learn more, I like the videos/articles/forums of Headphones.com and Crinacle.