Mine is originally using Baconreader while in the dorm community bathroom doing a deuce and seeing a mention of Sync. Installed and instantly became a user. Later on I had a problem with the app because I was running beta Android. Reached out to the dev and after a few fix attempts an update was posted that fixed the issue. To get that kind of support is rare and is why I have continued to stand by Sync all these years.
I was looking for a Reddit client for a long time. Tried searching all over Reddit and got many recommendations. Sync and Boost were the most suggested one but still I was confused. I decided to install all of them and compared the features, UI, Design myself. In the the end it was still between Sync and Boost but Sync won me over by having material design. I bought the pro version.