Having had both, I prefer deck stepped masts, for the reasons given. I use a heavy plate arch connected to the chines to prevent the mast support from intruding into the interior design. This arch is far stronger than any extension of the mast would be.
When I bury the side decks, the lee shrouds don't even slacken , in the least.
Those who build my boats with a keel stepped mast, eventually go for a deck stepped mast, when re-rigging.
Brent Swain, Boat designer, Builder, and author of "Origami Metal Boatbuilding"