You should download demos of any that interest you. That's what I did in my search and I ended up settling with Vegas. There's no MIDI, it's basically a pure multitracker, but you can sequence video and convert to all sorts of file formats within the SW.
Also, there are no proprietary audio file types in Vegas; it uses .wav files stored in a directory on your hard drive. For this reason, and many others, I've been much happier with Vegas than Cakewalk (which I used before).
dmc