It depends on the outlook.
For some players, Champions League glory is more attractive, for others defending their nation in a World Cup is the highlight of their careers.
From a marketing and global standpoint, it is definitely more watched and talked about than the CL simply because people who never watch football will make an exception to see the World Cup ''for the pride of the nation''
For fans it basically depends on if you prefer to see the best players of a country together or players from various countries together like in club football.
For me personally, the World Cup peaked in 2006. Look at these names: Zidane, Henry, Patrick Vieira, Ronaldo, Ronaldinho, Kaká, Van Nistelrooy, Fernando Torres, Nakamura, Buffon, Totti, Pirlo, Messi, C.Ronaldo, Beckham, Lampard, Gerrard, Rooney, Schweinsteiger, Ibrahimovic. These are just the first 20 names off the top of my head who were at that tournament. Never before or after you had so many players with a big impact in their clubs, ready made superstars, I suppose before that tournament the whole world was crazy thinking about all the possibilities of the tournament. Ok, it wasn't the greatest World Cup ever in the end but in terms of names and fan level of expectation, it was the best I can remember.