EMI have been kind to me tonight and let me listen to discs 3-6 from The Wall Immersion Boxset. The demos sound 1,000,000 times better than The Wall Under Construction bootleg that has been doing the rounds for many years. If you were holding out from getting the boxset because you already have that bootleg, then you really need to upgrade! 
Listening to disc 5… Run Like Hell and Another Brick in the Wall Part 1 sound much better in demo form in terms of their arrangement compared to the finished arrangement on the final master album. You may disagree or agree. You will have to wait and see after you get the Immersion Boxset!
As I write, I have just started on the band demos from disc 5 (the first of the two demos discs)… just been listening to the Roger Waters home and studio demos. The band demos are the studio production demos that the band recorded to give them a starting point in the studio in terms of achieving the right sound they were after I would imagine.
Teacher Teacher, which later appeared on the final cut as The Heroes Return, sounds rather good in demo form. HAs a different feel to it in terms of the rhythms from the drums and rhythm guitar. Much more laid back.
Bedtime now so I shall say more about disc 6 tomorrow which is part two of the demos. Check out more on Pink Floyd The Wall Demos.