Injector/Valve Phasing

[Louis J. Plebani]

I'm sure that this has been discussed before, but for those of us who missed
it: Could someone clarify (or provide a reference) regarding injection/intake
valve phasing? The Red (Bosch) Book, in their discussion of Motronic (pg232),
talks about "preventing undesirable spary through open intake valves".
Hartmann's book on fuel injection systems suggests that one should inject
when the intake valves are open. What's the pro's and con's?