Woah. Best Question Time for me to return EVER.
The absolute editions are expensive, but gorgeous. However, for reading purposes, I would suggest the softcover smaller volumes. The absolute editions are REALLY heavy and REALLY bulky and do not lend themselves to curling up with a cup of hot tea and reading.
I currently have the originals, the Absolutes and a couple of the volumes. When I want to read one just for the pleasure of reading it, I usually go to the volumes so I don’t mind when they start looking….. extra well loved.
The extra content in the Absolute is wonderful, if you are particularly endeared towards that. Ultimately, though, if I were you, I would go on Amazon and get used copies of the volumes. Once you’re in love with them, then you can start collecting the pretty ones.
(Plus, there’s more than just Sandman to collect. There are multiple semi-connected things like Death: the time of your life, or Death: the high cost of living, or Sandman: Dreamhunters.)