Couple of quick things. I'm not saying "Yes, Deus Ex Machina is a good way for telling a story", I'm saying "It can be used". The issue with Immaereal's post is not that he says "Deus Ex'ing a story can it ruin it", it is his statement of
By saying anytime you immediately negate any possibility of there being some sort of value to a Deus Ex Machina, which is wrong to the core.
To quote O wonderful Wikipedia as you yourself have: "it can be intended to allow a story to continue when the writer has "painted himself into a corner" and sees no other way out, to surprise the audience, to bring the tale to a happy ending, or as a comedic device".
There are too many variables within any storytelling device to say "it is always bad" or "it is always good". Most critics? Perhaps. I'd certainly hope that most critics wouldn't be as brash as to ignore the virtues of a film or story because of a particular use of a story telling device.
I stand by my point
To summarise: Deus Ex Machina = mostly bad, but CAN be good.
-K9