The D-5/D-50 wasn't a Discman or Portable, it was a Skipman, and Transportable. Playing the thing while moving it was a mess.
I remember thinking at the time, "Geez, why don't the just buffer the data a second or two?"
But remember the Radio Shack Optimus CD-3400? Even the high-end press though it sounded almost as good as esoteric stuff priced in the thousands. I bought mine for $129. I compared it to players in the $2500 range, it sounded just like them...or, conversely, the $2500 players sounded just like a $179 Radio Shack player I got on sale. And it skipped when moved around too.
Glass half full/empty...depends on what you're buying and selling.