Can you share spells from wands/staves?

[Hypersmurf]

There are differences ... save DCs, for example ... but otherwise, woiuldn't it be mechanically simpler to have them work exactly the same?

That would mean that a fighter with an arcane scroll of Polymorph and a couple of cross-class ranks in Use Magic Device would qualify for a Prestige Class with the requirement "Ability to cast 4th level arcane spells".

-Hyp.