Cumulative. I cannot comment on how much more they weigh, but it's seems generally accepted they are heavy, compared to alternatives. In fact, they may be the heaviest choice for connecting rods, out there.
The rotating mass is one of those big factors allowing an engine to rev higher, and produce more power before flying apart.
Some argue Chrysler made the rods thicker and heavier, to make them stronger, because they had no other choice back in the day. But modern day, by comparison, we have improved metallurgy and engineering to make stronger and lighter weight rods.
IMO, the biggest reason to use six pack rods in a 440 HP engine rebuild is mostly to keep it factory original, in an area that doesn't really show. I would be tempted to use these rods in a numbers-matching restoration. But once I started putting in alternate heads, roller lifters, and other non-original items, I'd have to have some compelling reasons for staying with the original rods.