Tournement is harder
It's two different games but tournament is harder.
1) Tournament means you buy in and play till eliminated
2) You are often forced into coin flip situations before flop risking your whole stack.
3) You have to play until you are eliminated or win
It's not that you can't make money playing tourneys or that the play is better it's just that you are forced to play with a limited amount of money and the blinds increase (excluding rebuy events, even then you have to take into account your expected return on investment).
Cash games are a different story, at a table you don't find good ev, leave. You can rebuy if you get short but you think you have +ev. You can wait for good
hands and play the player vs. coin flips. You can choose your opponents by watching the table before hand. You don't see as many all-in pushes pre-flop.
Both games require different stratigies, cash games require constant evaulation of limited opponents. Tournaments require adjusting to new players and changing conditions over a single stretch.