With a decent quality mp3 you cannot tell the difference. Don't kid yourself.
it doesn`t matter. Even high bitrate MP3s throw out high and low end data that humans can`t technically hear to make the file smaller. The thing is that even tho humans cant hear those sounds we can perceive they`re missing coz they ad warmth to the remaining sounds. Give it a 3D aspect.
Lossless files are reconfigured to make them smaller and go through more processing which means lower sound quality. I like to keep it simple and high quality.
Also no MP3 player I`ve heard off can match the D/A converter on a Sony D-777 or D-EJ01 (the one I use):
I got em paired up with some nice foldable Sony D-55 Eggphones from 1991 that still sound dope.