Where to begin? Take a look at a CD player, even the newest one you can find, and then take a look at an older mp3 player. Now, at first glance, you wont see any real difference except in size. But its not what's on the outside that counts, its what's inside.
CD players require, as you might guess, a compact disc. These compact discs at most can only hold about 23 songs. 10 years ago that was the coolest thing you could have. But nowadays, you have mp3 players, which even the smallest of these players have enough memory to hold about 10 CD's worth of music. That alone makes them superior in every manner of the word, to conventional CD players. Couple this in with the fact that most CD players require at least two batteries, compared to the one smaller battery that powers most mp3 players, and that's a very good reason to say that mp3 players are better then CD players.
CD players have gotten much smaller and more compact over the years, but no matter how small they might become, they can never get smaller then the compact discs in which they play. That being said, they will always be generally the same size as a compact disc. Sometimes it may not be so easy for you to put something of that size into your pocket. Yet with an mp3 player, even the largest ones are much smaller then a CD player, and they can easily be fitted into your pockets, or purse, whichever you use. This reason also makes mp3 players far better then CD players.
One of the last major reasons that mp3 players are better than CD players, is the fact that not only can mp3 players be used to play music, but they can also be used to transfer files from one computer to another. Such a feat as this, not only makes them better than CD players, but nearly makes CD players seem obsolete. Although there are a number of reasons describing why mp3 players are better than CD players, these are the most important reasons. These are not opinions, these are facts.