I've done both. I can attest that intermittent fasting, at least for me, is WAY more sustainable ... and actually makes maintaining a calorie deficit easier too.
Hunger is a weird thing. People tend to assume that if you don't eat you'll just get hungrier and hungrier. The reality is that hunger comes in waves. If you can ride out a wave of hunger for 30 - 45 minutes it goes away. And the longer you don't eat, the less hungrier you get. I think this is because those waves of hunger tend to correspond to your eating habits. So if you're accustomed to eating lunch, you feel hungry around lunch time etc.
After a period of adaptation, when this just becomes the new normal, you can find that when it comes time to eat you just don't want to eat all that much either. It's weird, but cool, and seems to work well for a lot of people.
Then there is metabolic adaptation, which is thought to be the biggest contributor to people re-gaining any weight that they've lost. What happens is that after dropping around 10% of your body mass, your body kicks in a survival mechanism whereby it lowers your resting metabolic rate to adapt and try to slow the weight loss. This means that two people who weigh the exact same, one of which just dropped a bunch of weight to get there, will require different caloric intakes just to maintain their weight. The person who just cut weight will need 300 - 400 fewer calories per day than the person who didn't.
If you cut weight just by caloric restriction alone, this is DISASTROUS, because you are hungry and weak and miserable ... and you need to eat even less just to keep the weight off.
Which is why crash diets don't work. You start by making sacrifices, which is uncomfortable, and then when metabolic adaptation kicks in you stop seeing results unless you make even more sacrifices. People can't stick with it so they stop dieting and very quickly and easily regain the weight.
Intermittent fasting not only helps with hunger control, but there is research that suggests that it can also increase resting metabolic rate, which can help to counteract metabolic adaptation.
But even if it didn't boost RMR, the fact that it helps with hunger control and maintaining a calorie deficit alone would make it more sustainable for more people than just trying to eat less in general.