I recall hearing about Alovoa a year ago and while it sounds nice with no ads or paid features, being open source, and private data being encrypted I have to imagine the userbase is incredibly small relative to other services. Google Play lists it at over a thousand downloads but it's also available through F-Droid so that may not mean much. I have to imagine the userbase is mostly men which might prevent some users from joining or sticking around.

Either way (TL:DR) I'd be curious to see what your experiences are with open source dating apps or even apps designed around making friends.