The beauty of ReelDirector is that you can use clips you've trimmed/edited on the iPhone and work with a (very) basic timeline to produce a video story.
But there are limits. You'll need to plan your shots carefully to craft your story. Video and audio for each clip remains linked and you can't add a voice track. It's sort of iMovie Fisher-Price. That might sound a little harsh but I actually think being easy to use will encourage more people to give it a go.
This time I tested the app using the low quality setting and posted a video direct to YouTube, Kyte (and by email to Posterous). I was pleasantly surprised as the file was only 15 MB for a 2:30 video - that's not so big to move from your iPhone. My first attempt with a video of around 4 minutes in high quality produced a file well over 100 MB.
ReelDirector also lets you use clips produced with other iPhone apps. Since my video blog story was Super 8 cameras I produced a short clip on Vintage Movie Maker app using the 60's home movie filter and projector sound and then just dropped it into the ReelDirector timeline.
Something to keep in mind. ReelDirector added the Vintage Movie Maker clip in low quality, but in high quality it popped up an "incompatible" video message. This might just be a bug or the settings for the clips you import from another app might have to be adjusted. If you're a video blogger you might also think about producing a branded pre or post roll clip to store in the iPhone Camera Roll to use with ReelDirector.
I'm still thinking about how best to use this app in its current form but hopefully the developers Nexvio will add more features.