This entails many considerations, but we will try to be brief and to concentrate on fundamental concepts: just 7 minutes.
It doesn’t depend on the projects, or not only: it depends on your programme or programs, your business, your strategy, and so on
Surely there are many factors inherent to the projects themselves, but projects are created to meet some needs. You should choose the project better meeting your needs, goals and expectations; whose needs, goals and expectations ought to have been defined independently of the proposed projects
On the other hand, if you asked for some proposals … you should have some clear expectations regarding both the project in itself and the broader frame, i.e., programme, business and so on
Every project choice should bring along its own criteria which you should have defined immediately after having decided you needed such a project; in a few words, those criteria may vary according to the situation.
Your choice doesn’t depend on projects only: good Project Management and Programme Management entail a broad strategic view.