GPE is not bad, and at least it syncs with Google.
Pimlico has a better UI but doesn't sync with anything (syncevolution is broken on NITs currently)
I had issues with GarnetVM just erasing my Palm.
I haven't loaded KDE because its a lot of overhead for a little productivity. I might try it is it was just the libraries ported so I could install KDE apps I want and run them through Maemo without installing the FULL KDE.

Nokia NEEDS a good PIM for the tablet.