This saying fits the PSB when the M4U2 first time so - to say without direct comparison - heard.
Then quickly sets a "wow" feeling.
As soon as you hear it but comparing with real "high-end" headphones, he looks a bit old.
He is only good, but not "the best".
He certainly sounds not bad, but really great, he also does not sound.
What it lacks is a bit of space and above all uniformity.
Another proverb comes from Oscar Wilde, who once aptly said: I do not have enough money to give me what to buy cheap!
In order to avoid misunderstandings: The PSB M4U2 is certainly not cheap, but for the price but then not the right.
Then I pay rather more equal and then have the "right" headphones.
Regards Bogomir