I think the F bomb is said about 8 times in DmC. - 3 during the Succubus introduction, 1 as a random quote when you deplete one of her health bars - 1 at the entrance to Lilith's club - 2 times for Combichrist's song "What the F is wrong with you" at the end of the Lilith fight - 1 for "You don't F with a god"
The cyborg soldiers in MGR end up cussing a lot more.
Anyways, as far as the games go its a different emphasis. DmC is more like DMC, emphasis on varying combos for style and MGR is more like Ninja Gaiden with more emphasis on just killing things as cleanly and efficiently as possible.