Olympics is definitely the bigger stage and more prestigious stage..
But on the other hand, if you're a NHL owner, your insurance coverage doesn't cover the players that get selected... and IOC ain't chipping (I presume) in to offset that cost.. so can't really blame the NHL for taking a stance.
Not sure how they'll enforce the players that opt to leave for that 3-4 week window...
Not to mention the NHL can't even use any Olympic images or materials to promote their player or involvement.
Personally I don't think it's really a matter of what I 'care' about. I love seeing the NHL players in the Olympics, but I understand if the league chooses to withdraw. It's an easy choice when the games are in North America, and after having the Olympics in Canada the NHL couldn't tell it's Russian players they weren't getting their own games in Socchi. But back to back Olympics in Asia?
Some fans say the NHL is stupid and working against their own best interested if they don't go... but they've been sending the players to the Olympics for 20 years now. If the NHL doesn't believe they're seeing any real benefit out of it, I would tend to believe them here.
Another factor that I don't see anyone else mention, if you grow the game in that part of the world the most immediate beneficiary would likely be the KHL. They can make it work geographically, already have a team in China and have plans for more including South Korea. That doesn't bother me at all and as a fan I wish them the best, but from a business perspective the NHL isn't going to want help give it's biggest and only rival a leg up.