On Android I use Reddit Sync[1] (which has an ad-free pro version I paid a one-time $5 fee for).
I worry about the day they discontinue old.reddit.com, or decide to cripple third-party apps in order to steer people toward their official apps. I wouldn't put it past them to do something like this. All it takes is a new CEO, or their investors, wanting to see more profit. They'll probably lose users but I bet the amount of people who use Reddit like I do is decreasing over time (speculation, maybe I'm wrong) so it might not be a significant amount.
1. https://play.google.com/store/apps/developer?id=Red+Apps+LTD...