Waldner is widely regarded as the greatest table tennis player of all time. I was a little kid when he was at his prime so can't really judge, but I'm not sure he was in fact the greatest. Seems to me like there were a lot of Asians champions, but calling one of them the GOAT wouldn't be as exciting as calling Waldner that.
Right now the Chinese have total control over the sport. The only European guy that challenges them is Timo Boll
(Germany), but he is declining. In terms of popularity Boll is almost like Federer, by far the most loved player. One of the reasons is that Chinese players kinda lack personality so there aren't many devoted fans outside China.
Anyways, the most popular Chinese guy right now is Ma Long
. He is currently the world #3, but rankings in TT can be way more misleading than in tennis, and he is actually the strongest player in the world by a fair margin.
Another great video: