Could anyone brief me about the 3-2 program for CS at LACs like Reed, Haverford, Grinnell, Bowdoin

I want to know what the 3-2 program is about and how it works and if it is worth it. I also want to know if the financial aid package would be transferred when you change your college. I would also like for someone to rank the CS programs at Haverford, Swarthmore, Bowdoin, Grinnell, Reed and Carlton. What are the pros and cons of each's CS programme, and their generosity in terms of international financial aid. I would also like if someone commented on the 4+! Masters in CS programme at Haverford