Hello,
I was able to download Fedora 21 easily, however when I click on the Checksum link to download the file...it does not work. I have not had any issues with installation, so the file definitely works, but I thought I would bring that to your attention as it is offered as an option. I have attached a screen shot of the page you get if you click on the file. If I am doing anything wrong here please let me know, and if you have any questions please don't hesitate to get back to me.
Sid