It doesn’ t depend on the projects, or not only: it depends on your programme or programs, your business, your strategy, and so on.
Sure, there are many factors inherent to the projects in themselves, but projects are created to meet some needs. You should choose the one meeting your needs, goals and expectations to the greater extent.
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, they may vary according to the situation.
Your choice doesn’t depend on projects only.