I see pretty much the same disassembly and know those extra files and the extra file size help associate it with the source file but are there any other differences?
Not really that different, they can't be. In essence it can contain line number information that associates a specific instruction with a line of source code and symbol table information that allows the debugger to display the actual name you give a variable. Besides that it really isn't that different, there are different types of debug builds, one that puts the information in the OBJ file and another that stores it in a PDB file but the information is essentially the same.