I exported it out of AE as a lossless quicktime animation.
Next thing i did was to export it out of quicktime as a MOV :H.264, double pass.
First the file size was just 17 MB, it astounded me, so I exported it again.
But now i used: HDV 1080, it looked even better (file size 64mb) but when i uploaded it onto vimeo my ramp was looking awful, even though i uploaded in HD?
Take a look for yourself:http://vimeo.com/3057769 (password: azerty789)
By not using compressed formats. ;-) Ultimately there will always be some minor banding, especially with MPEG derivatives that use chroma undersampling to increase compression efficiency. Unless you can employ the usual tricks like introducing minor noise or adaptive blurring to enforce a different block pattern, there's no way to completely avoid it. Also look into using other tools to do the actual compression. QT Pro is not bad, but other tools may be even better...