I’ve used it on my Treo Pro a bit. The voice quality is greatly improved when compared with the previous version, but is still very poor over 3G. There is a lot of dropped data which leads to very choppy audio for both parties. For text chat, however, Skype has one of the best Windows Mobile interfaces out there. Even group chat is handled very well, and the interface works great with D-pad navigation. Some of the UI elements are so small that they’re not very finger-friendly. Audio is still output via the speaker rather than the earpiece, so a headset is probably a requirement.

I have not had a chance to try it on WiFi, but to be honest, anywhere I’m close to WiFi, I usually have my 2710p, and would much rather use Skype on it. For voice calls on my phone, I’ll just use the phone since I don’t make international calls and have plenty of minutes available.

It’ll be interesting to see how well this version works.

One of my long term complaints about Skype on WM has been how resource hungry it is. Now, with the 400Mhz and 530Mhz processor phones its not that much of a problem, but on the older ones with 200mhz chips, it was pretty unusable, unless you overclocked it.

Another was as you mentioned, a heavier drain on battery life which can be bad enough with wifi / 3g running.