I would like to get your own opinion on the following thing, which might pertain to any tabletop RPG, as well.
+++SPOILER ALERT BELOW on Purge the Unclean+++
Particularly, I refer to the climax of Shades on Twilight where Mr.Agamorr gets to help the PCs in their final bloody fight with Dark Eldar.
Would you prefer to run the combat as usual, in accordance with the given stats of each NPC involved, or sacrifice the game mechanics and narrate something along the lines:
"Slamming your last clip into your autogun, aiming at the dark, vicious-looking yet strangely elegant silhouettes of the dimly lit cargo hold, you almost feel like you are looking into the eyes of your own doom. As they approach in a fluid and bewildering manner towards your line of fire, suddenly you hear a deep voice echoing against the hold's walls like thunder: "Fur Kaiser und Vaterland!" accompanied by the distinctive deafening roar of heavy fire. You turn your head, and see brother Agamorr blasting at the xenos from the hip, with a bolt pistol, with a loudener attached to it... two silhouettes have exploded in a bloody pulp already, but was that blood, really? ... And soon they were rallied. Happy end. blah-blah.".
Basically, in the first case (if we use stats and roll the dice) the Space Marine (who is the deus ex machina in this case) may roll 00 and fail, thus ruining the dramatic moment. He may as well miss, or hit a friendly taget, or have his weapon jammed, etc. However, this is realistic.
In the second case, the Space Marine is sure to act as needed, but the verisimilitude of the situation will inevitably be impaired.
What would be your personal preference?