When downloading from mega4up with premium account I'm getting files with only 1kb.
I've the same issue as DeadTwista with mega4up. Every file is only 1kb with the blue button, but perfectly fine if you use the straight link. It's happening on all downloads today.
A couple of examples: viewtopic.php?f=121&t=4132262
viewtopic.php?f=121&t=4132370