These videos were downloaded from United Streaming, imported into iMovie and then exported using several different compression settings. The goal was to see the different buffering rates versus the quality of video.
MV4 Format
File size = 7mb
MPEG-4 @H.264
File size = 2.2mb
MPEG-4 @intermediate
File size = 2.5mb
MPEG-4 @basic
File size = 684kb
I think in general, the MV4 took the longest to buffer. With a larger video, I can see where this will run into problems. At 7mb verus 2.2 (for H.264) it is more than 3x the file size. However, the clarity of the MV4 video versus the H.264 is not that much more remarkable.
The intermediate level degrades a bit more from the H.264 compression, but oddly is larger in size. However, it seemed to load a bit faster in my computer’s cache.
The basic settings degrade the file too much. It is the smallest file size and loads almost instantly in the computer’s cache. However, I think the tradeoff is just too great.
My recommendations: for the type of videos produced by the district, I believe exporting the file as an MPEG-4 using the H.264 compression rate seems to be the most optimal format.
Saved for iPod - MV4 format [1:23m]: 
MPEG-4 H.264 [1:23m]: 