I'm working on a project that will involve having a couple thousand short videos online. I haven't done anything with online video before and this is all a bit new to me, so I am looking for some general advice...

I would like to use Flowplayer, and I would like to encode the videos as H264s. I am enamoured with Flowplayer's slow motion feature, which if I understand correctly, is only available using a Wowza server.

I'm wondering: Is it advisable to use a delivery network of some sort? (Flowplayer seems to have a partnership with HDDN, and recommends them. http://www.hddn.com/) Or would I be better off purchasing Wowza and installing it on our own server? (At first glance, it looks as though signing up with a network like HDDN is much simpler, but perhaps there are problems that come along with this...?)

Any tips / warnings of imminent peril would be much appreciated. Thanks in advance.