Which codec is best to use

Hi everyone,

I'm new on pond5, started about a month ago.
I'm working with vectors and photos, but i also start to shoot some video, so i need some advise about codecs.
I use Canon EOS 5D Mark II. Native codec is H.264 in .MOV file container.
Should i upload videos unmodified or it is better to convert in some other codec using MPEG streamclip?

QT PJPEG

Thank's Rekindle. :)