Thanks for asking! The community is about 15,000 users, maybe 100-300 DAU, tests complete in as little as 10 hours for 20 ranks or up to a couple days if you have a lot of niche filters set for your rankers (age, sex, location).

The best ROI I have found is on Apple and Android app stores. I tried Facebook, Tiktok & others and have found them very expensive with little return (though I admit I'm not marketing expert).

As for Photofeeler.. I actually created this app because I found the way it rated me 1-10 fairly harmful to my mental health. RankPic has users rank your photos best to worst, so it's just against yourself. Additionally you can get more mileage out of each test as you can upload up to 6 photos at a time.