Yes, I owned several MP3 players of the era, one of them an iPod video. I found the ipod
at the time to be one of the most frustrating to load media onto - as one memorable example, it wouldn't let me load .mp4s into the 'TV' folder, because .mp4s are 'Movies'. No argument will be entered into. wtf?
Loading music was no better or worse than other players I had, but iTunes was still horrendous bloatware. Why do I need to install Quicktime - absolutely and utterly useless to me - to simply move files from hard drive to ipod?! Some MP3 players I had just let you drag and drop with a file explorer and they would 'just work', plus you could use the software to do it 'properly' if you felt like. One chinese knock-off I had simply played the songs in the order you copied them on, which was weird :) Then there's things like radios - ipod had none, despite it being a clear feature people wanted for years.
But yes, I had several MP3 players of the era, and the ipod was nothing special in terms of user experience. The hardware case was pretty, admittedly.
People are viewing the early digital music player market with the rosy-coloured glasses of historical revisionism. Apple are top dog now, so it somehow stands to reason they always were? Logical fallacy. The early ipods weren't great, and it wasn't Apple out there leading us all into the digital music new world, there was a passel of competitors.
I think you also underestimate marketing - higher market share does not mean that the product is inherently better (betamax vs VHS, anyone? Or the OS war of your choice?). Apple has an incredible marketing team, and frankly good marketing does mean something significant, or there wouldn't be so much money in it.