M.B.,
I also always respect your opinion (Well, except maybe that any change is better than none

).
I am well aware of the numbers that Raynor posted. One thing that is missing, though, is cost of the weapons.
PPB V: 500 min, 300 rad
APB V: 150 min, 50 rad
APB VI: 175 min, 60 rad
notice that I didn't compare to APB XII, because APB V or VI is what you get for the cost of PPB V (it goes without saying that APB XII is superior to PPB V. Now, I said it. D'oh!

). If you stick to APB V instead of APB VI, you can use 100k worth of research to use for better sensors and/or ecm.
a basic LC design with PPB V costs 7600 min
a basic LC design with APB V costs 5500 min
so when comparing ships you should do in a 3:4 ratio. run some tests. hopefully you will agree that it balances out
a small weapon platform stuffed with PPB costs 3170 min
a small weapon platform stuffed with APB costs 1070 min
this can be very important for "Last minute" defense
I stand by my opinion that "balancing" the PPB (if that is needed at all) is just a matter of doubling the cost. This will "blow" another 140k worth of research (IMHO, better spent elsewhere

).
Rollo