Well that explains a fair bit. Some of the footage didn't seem up to standard for Vimeo or GoPro!
Vimeo has your vid at 960p but I'm sure they only use 30fps. Along with your rendering/compression they would have converted whatever you loaded to H.264/AAC audio 30fps and 5Mbps(HD).
When editing for Vimeo upload - I try to stay as close to Vimeo's settings for the whole process or compress my footage to H.264/AAC, 5Mbps
The Mbps is the most critical thing when it comes to file size and render speed. eg:2min of HD exported from fcp (current settings) gave me a file 722MB with 90fps and 59Mbps. I used Mpegstreamclip to re-compress to 5Mbps and I get a file 10% of the size. If I'm concerned about load time I drop Mbps down to 2.5 and have even used 2Mbps without losing to much quality. You vid looks like it was around 2Mbps.
16GB!!!!! Awesome

my 8GB takes 4hrs to render 90 minuets of 1080p when set to maximise the dual core. I'm not a big believer in HD unless I need to crop the footage. 576p is plenty good enough even on a 50" screen. But some customers insist even when the final product will be burned to DVD video
