Many comparisons of medieval and modern music have already been discussed. I will add a few more worth considering.
One point of comparison between medieval music and today's music comes from their influences. Music today tends to be influenced by many different cultures. This has lent it a variety that simply did not exist in medieval Europe. For instance, West African polyrhythmic beats and Latin American syncopation are common elements in much of today's music, regardless of its origin. Even music with a very regional identity will still contain influences from other places and peoples. Therefore, if you listen to music today of just about any genre, you can detect influences from around the world. Conversely, medieval Europe was an insular world with few outside contacts. Therefore its music was much more homegrown with less variety.
Language is also something to consider. Most music of medieval Europe was liturgical and therefore sung in Latin. As such, the lyrics were not understood...
(The entire section contains 4 answers and 933 words.)