Depending on your background, you’re probably familiar with at least one of these 2 frameworks.
Marketing Personas owe their existence to advertising agencies and usually depict the way a customer/user looks, acts and feel like. They’re “day-in-the-life archetype descriptions” - slices of life. In a way, they’re very similar to the character sheets a writer comes up with when planning their next novel or short story. They help evoke images, they can be used as backdrops for larger stories and have powerful generative properties when it comes to designing human-sounding messages. Personas excel at reminding marketers that they’re in fact talking to people, not bundles of needs and wants. They’re data visualisations at best. Context bearers would be a good name for their role.
However, to say that their predictive powers are lacking is an understatement. You cannot plan features based on a persona. You cannot derive solid inisghts based on it. The persona is the lowest common denominator, so it’s a good testing tool for messages and new features. It can lend flavour to your writing, design or interaction, but it will not reveal it in the planning phase.
For that, you need the Jobs to be Done framework. JTBD is little more than a mindset shift. Its techniques are not new, but they are useful and - for whatever reason - seldomly used. Where Personas give you the “How”, JTBD forces you to find out the “Why” and “What”. Relying on a combination of qualitative and quantitative research, it helps you flesh out the real reasons people choose to use/ buy/ view your product (and by product I mean ad, film, piece of software and so on). The logic behind this is that people “hire” products to satisfy needs, to perform a task. If you’re not familiar with the concept, start with the Jobs To Be Done article on Harvard Business Review. It’s a good primer.
It’s not that one is better than the other (albeit the latter is evidently more scientific). They serve different purposes and should be used together - even if just as a precaution.