I think a demon is the more logical choice in this case, considering Sam defeated it (or at least survived) by strangling it...
That's not what happened at all! Time was reset, he was pulled out of the situation, you even said in 'The Boogiem*n' thread that you agree with this notion over it being a dream.
There was no way Sam would have survived that and his stranglehold on Satan had absolutely no effect. It was like strangling a mannequin (and this has nothing to do with the fact that one could clearly see that it was BTS wise). Which has me suddenly finding Al's logic pretty stupid:
"If you can touch him you can hurt him."
Shouldn't he know better that a mere mortal could never dent Satan? He's the one who actually believed in Satan.
Of course I've heard of demons and by the way that was worded a bit on the rude side but I've never seen them as representatives of Satan and that belief is actually highly exaggerated in a lot of fiction.
Believe it or not Demons are religiously associated with Angels. Satan himself is actually an Angel, a creation of God like any other, originally known as Lucifer which means 'Light'.
Early Christianity regarded Demons as the offspring of earth descended Angels and mortal women, I believe this is discussed in The Book of Genesis.
Some interpret it slightly differently, that they were born as the souls left behind by these offspring when they perished.
There is also a belief that Demons are fallen Angels, those who were banished from Heaven for rebelling against God though there are arguments that Fallen Angels are much more powerful than demons.
Whatever way one looks at it one thing is agreed upon by all, Demons originate in some form from Angels but not all versions associate them with Lucifer.
Sources:
http://www.tbm.org/origindemons.htm
http://www.gotquestions.org/fallen-angels.html
http://www.biblestudyproject.org/satan-and-demons-messianic.htm
http://www.newadvent.org/cathen/04713a.htm
The character we see in
Quantum Leap is quite clearly stated to be Satan himself.
1.) The DVD episode summary screen says
"Sam matches wits with the Devil" or something to that effect (actually the way they wrote this particular episode summary is idiotic because it gives the whole thing away but I digress)
2.) The being disguised as Al clearly identified himself as Satan. Besides I don't believe a Demon or even an Angel could guise himself like that. Angel didn't guise herself when she appeared to Sam, in fact she was a bit TOO open about her identity hehe. The classic Angel who set the standards, Clarence (a fact that was actually point out in
'It's a Wonderful Leap') didn't appear to James Stewart in guise.
It is my head canon that he did however send representatives later in the form of Alia and Zoey.