The funny thing about it is that you'll hear the differences if that is what you believe and you've never tested yourself properly (the incredible power of your brain). However - after testing and knowing you stop worrying about the differences in file formats (knowing you can't differentiate anyway). This then lets you just enjoy the music and the only question you need to answer then is if there is a better mastering of the album you want.
The other good thing for me (knowing my limitations) is if there is an album I can't get on easily CD, it's normally available on iTunes (aac256). Now there is no hesitation buying the music I want to hear.
You're preaching to the choir brother. I use to swear I could hear the difference between 320 MP3 and FLAC. Maybe I could with the inferior software on my previous music player. Now with Viper4Android (V4A) on my Note 3, I will likely re-encoded all my CDs to 320 MP3 to save space.
After my experience with the HiFiMAN HM-802, I have zero interest in the 901. It's the same user interface. The 802 couldn't compete with my Note 3 (with V4A). On the 802 someone else chooses the sound signature for you with the various amp cards. It sounded good, but the Note 3 sounds better and more dynamic with way deeper sub-bass because I can choose the sound with various changes.