Working 2-way sync between KDE PIM and PDA / Phone?

Hi!

My WristPDA died and I'm currently looking for a new PDA or Smartphone.

I'm absolutely willing to choose my new device depending on how well it
works together with KDE PIM.

Is there any device (or, even better, sync protocol) out there which
allows flawless bidirectional syncs of at least addresses and schedules?

I wasn't able to find a definitive answer out there on the web so far, but
in general the information I found (mainly on mailing lists) was not too
promising. :-(

Thanks a lot in advance for any answers!

Greetings,

  Gunter