I suppose it was improved in the 0.9 versions, when I tried it months ago during my search for the perfect Exposé + Spaces clone (result: there's no acceptable clone), the description sounded fantastic, but I never witnessed a program failing to live up such claims so spectacularly. And it leaked memory like hell.
BTW, Dexpot was updated a couple of days ago. Better Vista support, and now runs in x64 Windows.