I can't believe that we don't have a specific thread regarding this subject. So, I'll post this. Feel free to argue the merits of your lists, and some of us we'll be compelled to defend ours.
Here are my guilty suspects.
e. Philip Glass
f. John Cage
Mozart created some of the most beautiful and memorable music in Classical era. I just don't understand the adulation he received today. Tchaikovsky, in my opinion, is very competent composer, but his music doesn't ''do'' me. Same to Mahler' symphonies.
On, the other hand, we can argue that Schubert is as popular as ever, but there are some, who think that he's only a ''gifted amatuer'' (that's bs, btw). Monteverdi's contribution to opera was often overlooked, while Schoenberg's twelve-tone system continues to baffle listeners..
I am tempted to include LvB in the overrated, but I don't wanna die..
It's important to distinguish between ''overrated'' and ''underappreciated''.
What's in your list?