But be sure people understand your choices. When you ask people to choose between things that they don't understand, they'll usually choose neither. I'm not so sure about your software, though. I'd better be safe and buy the other program. If you're selling software for webmasters, it's okay to let them choose between downloading it from mirror site one or mirror site two.
Webmasters understand what mirror sites are.
But if you're selling a program for the home and hobby market, and you're asking people to choose between mirror sites, you're going to confuse people, and lose sales. Prospects for your home and hobby software don't have a clue what a mirror site is. Confused people won't buy your software. You work hard to get people to visit your web site. Make it easy for them to choose to buy something while they're there.