So here I am, a month after Giftiz featuring promotion started. The question is now, does Giftiz significantly increase you downloads? The answer is: yes, if your download numbers were very small.
I believe you can make decent money from ad supported game when you reach about 100.000 downloads in the first month based on other people's experience and my own humble beginnings. Giftiz gave me approximately 2300 downloads in a month - 2000 in the first five days.
This might be enough to generate initial interest. A spike in your downloads that will make Google Play store algorithm to notice you and show your game in the Top New Free games. Moreover 20% of these installs come from France. Giftiz is a French company after all. This will give you significant boost in French store.
But it's not good for anything else. The people coming from Giftiz might be able to generate about $10 - $20 revenue on AdMob. They install your game, play until they finish the mission and leave immediately afterwards.
ConclusionHere is the final graph of daily installs and uninstalls. You can see that the first day of featuring the downloads skyrocketed, but so did uninstalls.
So what does that mean? When you get a free offer from Giftiz to be featured after your first month in the store, you are helping them more than they are helping you - they need your game. If you were to get the offer to be featured during your first month, go for it. Unless you are already seeing thousands of daily installs.
Including the Giftiz SDK is very simple, but there's another risk included - your game will partly depend on their SDK and their service.