Coming from Creative Zen headphones connected to a Sound Blaster AE-5 Plus sound card, the difference is clearly impressive. In my main use of music and gaming, I clearly distinguish more sounds and effects with detail and exceptional stable quality. I preferred not to go for gaming headsets because Hi-Fi speakers in this price range (60€ - 80€) deliver sound for professional use with the sound card reaching a sampling rate of 32bit / 192kHz... so headphones like Mackie with 33Ω resistance highlight the sound with detail.

I don't know how weak they can be if you use them without an amplifier, as 93db sensitivity for secondary use on a tablet or mobile phone is low. In terms of build quality, it has plastic that needs attention to wear, while it looks a bit "fake". They come with a long cable, carrying case, and a 6.3" adapter. If you find them on sale for less than 70€, they are a top value for money choice.

Similarly, for the AKG K240 MKii headphones which are open-back like the Audio Technica ATH-M30x, reviews on rtings mentioned that the sound "loses" somewhere, but of course they are for a different job like mixing, listening to the instrument to compose music. For PC use, they impressed me from the first moment!

Extremely good headphones with natural, balanced, and clear sound, good isolation, and construction. They are lightweight and comfortable (although this is somewhat subjective as it depends on how they fit each person). All this from a company whose name phonetically resembles the French Maquis.
Now, because comparisons help us form opinions more easily, they are not better than the Audio Technica M40X in sound reproduction, especially in the midrange. However, at the price of 59 euros they were clearly a value for money.
Update: I have to remove one star because after 3 years of use, the earpads completely peeled off. Completely and everywhere, in all areas, as if they had an expiration date.