Eh, not that good, some are even terrible. The one of White Queen works perfectly though in my opinion, particularly Freddie seemingly appearing at the start when it was really just too dark to see his face past his hair :P
Night Comes Down has a pretty nice one, not sure what relevance photos of them in their early lives has to do with the song though.
The 'I reign with my left hand' section of Black Queen was good because the video actually synced with the audio, rest was average. Understandable because that's the only part that there's video of them performing anyway.
Teo Torriate is pretty good. Action's good, though whoever made that had the advantage of a full pro shot recording of it live :P
I could add to this list:
1.A kind Of Magic(Highlander Version) link
2.My Life Has Been Saved(1989 version):link
3.Roger Taylor-Dear Mr. Murdoch 2011: link