I 100% do. I think mp3 is a good compromise of sound and space. It's also the format I'm used to. Just like how people swear by physical record. If I'm at a get together and hear mp3 quality, I'm at home.
That being said, I have my absolute favorites in flac for my iPod 5th gen video I rebuilt. The 5th gen's dac, Wolfson, is a solid little dac for the day and age. Got Rockbox loaded up and I'm ace, but I've hard saved all the Apple firmware for every model in case the time came to sell them. Old iPods could be an investment someday and I own every gen in multiples.