As I said on Commons-l. With Firefox I was given an esteem of 2 h for a 190 MB file, with Chromium about 10 min. With Firefox I never got more than 50-100 KB/s, with Chromium never more than 200-300 (monitored with nethogs).
I have a very stable 10 Mb/s full duplex connection.
I tested only a single time, but standard upload usually takes all my bandwidth. If you need more info just tell me what to do, I guess I should also try via API to exclude browsers problems but I don't know how to do it.