It's a great way to get software that you wouldn't normally buy. I downloaded EASEUS Data Recovery Wizard 5.0.1 from them some time ago.
Just last night I was looking online for a recovery program that could restore an accidentally formatted MicroSD card. All of the free ones limit you to try the program, but to actually recover it usually costs about $30 for the full version. I had completely forgotten that I downloaded DRW from GoTD, but figured I would check my list of progs I've gotten through the years from them, and there it was. 30 minutes later, 140+ pics recovered.
They've been on my dailies list for quite some time now, new offer goes live the exact same time as Amazon's DoTD. Hit or miss software definitely, but it's always safe and free. I usually wait until there are a good number of ratings/comments to avoid having to do the research myself.