A landlord is the person who owns a property and rents it out to tenants. They maintain the property, set the rental terms and collect rent payments from tenants.
Landlords are responsible for making sure that their rental property is livable and in good condition. They also must ensure that tenants are complying with terms of the rental contract. They may be required to fix plumbing and heating issues or evict a tenant for breaking their contract.
While both have their pros and cons, it really depends on what you're looking for as a tenant.
Landlords own the property, so each time you need something fixed or have a question, you're going directly to the owner. Because the landlord creates your rental contract, you may be able to negotiate and change the terms, unlike with a property management company. You'll likely have a less formal relationship with your landlord.
Since landlords are a one-man show, they'll often be juggling multiple properties and it may take a little longer for them to fix issues or respond your requests. They don't usually have access to resources like property management companies do, like contracted plumbers or yard care teams. Landlords often don't have an organized process for keeping track of properties and may make mistakes when dealing with tenants.