Advantages/disadvantages of using symmetric encryption function as hash function? Next to the traditional MD5 and SHA-1, other hashing algorithms exist based on symmetric encryption algorithms. An example is the Matyas–Meyer–Oseas construction.

What are the advantages/disadvantages of this approach instead of using traditional hash functions, such as MD5 and SHA-1?
The disadvantage of this approach is that block ciphers are not necessarily designed with this goal in mind. Specifically, AES has related-key problems, and DES completely breaks in Davies-Meyer. In general, block ciphers are not necessarily ideal ciphers and should be used as intended which is as pseudorandom permutations. In contrast, SHA256 and the like were constructed specifically with the collision resistance goal in mind. It doesn't mean that they achieve this goal, but they have a far better chance.