After launching on Saturday, MEGA has had a few issues between running extremely low and having a few small bugs in the user interface. According to Kim Dotcom, they are working on fixes for the bugs and issues with some of their servers.
“#Mega is slowly stabilizing. Still fixing small bugs and issues with some servers. You can expect a smooth experience soon.”
Considering how awesome the 50GB of free storage is, I hope it will be easier to use when the bug fixes come out soon!