What's your favorite thing about AppSumo?

Just recently I've partnered with AppSumo to offer my E-Book "Start With A Side-Project" on their marketplace, and I'm liking it. So far I made few sales with minimum marketing efforts, I'm looking forward to get some Sumolings reviews and respond to the readers!

What's your favourite thing about AppSumo?

BTW if anyone wants to check out my E-Book, it's on a limited time discount on AppSumo - https://appsumo.com/marketplace-start-with-a-side-project/