A lot of AMVs are synched up just fine and perhaps feature a bunch of cool effects that make them popular in the AMV crowd. However, I for one am sick of random pretty anime set to techno mixes, spastic comedy set to upbeat songs, and action scenes set to heavy metal. The thing that makes AMVs good are beyond just he technical skill of the creator, but more importantly how the song and anime fit together.
And even though, I am tired of vague meanings linked to all sorts of shows. Just about every show can be linked to a Linkin Park song because their lyrics and sound are so general that anything can be said to match up. What I like to see are more specific matches. A song and anime with unique tones that miraculously match up. I consider this an example.