Man MegaShare needs FTP-upload feature, I find myself to be uncapable to upload via browser very frequently. Not certain is the problem on my server's side or yours but it's still very frustrating.
This FTP upload feature has been repeated numerous times. Have you tried remote-upload? Because I always get a constant of 50mb/s at the very least.
You can expect the FTP upload feature when v2 is launched, rest assured.