I've just uploaded 5,000 files to an Office 365 environment using SkyDrive Pro. The files were small - 8 KB each, but I thought it would be interesting to look at the transfer rate.
It looks like it averaged 26 files a minute over 2 hours 24 minutes. Not the fastest way to get files up, but handy if you aren't in a rush. It looks like SkyDrive Pro throttles the upload so that your machine/bandwidth/server isn't maxed out.
I'm based in Sydney, Australia. More than likely, the server is based in the Singapore data centre. YMMV.