Mmmm the only common is both of them use a ton of money to buy european top players who are old or with not so much space in europe, but Saudi go one step further and start to own players who were already in top condition, plus Saudi football is way advanced than chinesse one, you can see it on the National team, and one last thing is they are more closer to europe in travel distance and, a lot of players who are muslims wants to go there because of religion.
Saudi league is quite different with Chinese league. Even if both of them used ton of money, Saudi becomes more selective in signing top European players. If the players can't contribute well, Saudi teams easily kick them. Meanwhile Chinese teams, I doubt they can do the same as Saudi teams. Sure, Saudi teams have bigger amount of money. So they have no problem if they must waste money. 
However, we can't deny that Saudi league has a better quality if we compare with Chinese league. We can see that Saudi team can play well in international competition such as FIFA club world cup or AFC Champions League.