From our own testing, we've also noted a stability improvement. For instance, version 0.2.0.1 (i.e. the beta version) would crash when loading group chat logs. This appears to have improved with the latest version.
Skype said on its Skype for Windows Phone Has Arrived,
Since releasing the initial beta app in February, we have received very positive and helpful feedback that has allowed us to improve the app.
Furthermore,
This is the first of many releases to come for Windows Phone, so stay tuned for even more capabilities in the future. We believe in the great potential of the Windows Phone platform and will continue to invest over time to enable experiences unmatched by any other app in the market.
You can install Skype on your Windows Phone 7 device via our application directory.