Flash Media Server vs WMV output

[SIZE=2]Don’t know if this is in the right place or not so feel free to move it. I am currently trying to make a decision on what is the best possible format to stream videos. Right now I know the pros and cons of using flv files (Flash media server) but cant base my decision on why I would choose that over WMV. Also one major concern is that these videos will be dnyamically created so there will be some development on it.[/SIZE]
[SIZE=2]So lets hear it… Who has the best video quality, size, market penetration, etc, etc.[/SIZE]

[SIZE=2]Thanks in advance.[/SIZE]