Neither is more or less dramatic than the other, to me, I’m afraid. The spaces do the work.
But I’d settle for either version without argument as long as the spaces are there. The em-dash with no spaces is like a hyphen saying “I know these two are supposed to be connected, but they’d both rather not be.”
I feel you. Trying to turn off auto-incorrection of some things, like constructing dates or converting quotes, has cost so many person-hours that we could probably increase productivity just by writing by hand again…
Hey, come on. There are two O’s separated by a double U!