In this model the project timeline is decided before the development starts. Clients having a proper goal of their product release should prefer this model. In this model the budget stays the same as agreed earlier before the development starts.
In this model the requirements are not clear and the client pays for the number of hours to the developer, who is outsourced to the client. The client can decide the number of hours to be spent on the project.This model has lot of communication and transparency.
In this model client may want additional resources. This engagement is cost-effective and team interaction is ensured.This model helps in achieving the deadline on time as there is continuous communication during the whole process.