I think lichess.org is far superior in that it has a super-polished UX in ways that are not immediately obvious. After I made the switch from chess.com in 2014 (I had the paid features), it was always extremely annoying to come back. Also lichess.org gives you most of what chess.com tries to upsell you on, for free. As it happens I've re-validated this over the last few days with dozens of games on chess.com. A singl…
The tournament UI has been broken on iOS for years. It doesn't register taps properly and some UI elements are not shown where they should be. OTOH, the website works pretty well on mobile, scrolling aside. In general, I also had the feeling that the lichess UI is a bit more immediate, it was easier for me to get around. But I think a big difference is not in features or UX, but the behaviour of the players. Because…
I almost never concede at my (low) level: at my level it's very possible that someone lets me go into a stalemate which is preferable to a loss.