It depends at which level and which type of events one plays.
At GM level, reliability is a must, and lately there was a resurgence of supremacy of the side with space advantage, sometimes even sacrificing development to ensure long term advantage, even in endgames.
At 2500+, opening does matter. Without proper knowledge, it is impossible to play aggressive positions that are also reliable: if you do not want to study thorough opening theory, but still you want to play sharp, then you are forced to look for sharp sidelines, but much less reliable. And after a couple of games the surprise effect is gone, people will prepare specially for your sideline, and you'll have wasted time in preparing some funny line only for a game or two.
at <2300, one can play virtually any opening that is not trash.
E.g., even if the Albin Countergambit is a huge gamble at 2600+, at 2200 is just about as effective as any other opening.
Also, solidity is a big virtue in Round robin events with small number of players (4-8) and in individual matches.
In an Open tourney, you gotta win a lot of games if you aim to a good placement, hence the need to play unbalancing positions.
What do I look for in an opening ?
I like to put pressure on my opponent, and especially I like when I can grab a long term advantage (structural or material) so that he has to demonstrate very quickly that he has something, otherwise he'll be struggling.
Psychologically it's a huge pressure to put on opponents
From the theoretical perspective, I prefer to have at least one option rather stable, so that I do not have to keep updated every week or so.