>In my database designer I'm assigning relationships between all the primaries keys in my tables, that then I drag onto the forms I'll be using. My boss, who knows some VFP says they are not truly reliable and that it's better to create your own as you go. What do you guys think?

There is critical difference between RI persistent relationships created by Database Designer and temp relationships created by SET REALTION (or by DE Builder). The first ones are used for triggers only i.e. provide data integrity. The seconds one are used to move records pointers in logically related tables simultaneously, i.e. it eliminates needs for SEEK().
What relationships are better? Mostly, it's question of developer's preference. My preference is to use RI relationships and not to use temp relationships.