Since presence awarness is integrated in the Lotus Notes client I refused to use the stand-alone Sametime client. Today I installed the Sametime 7.5 beta 3 client (and by end of the week there should be a Beta 4) and I am rethinking my decision.
The stand-alone client lets me manage separate communities very easy, so I can connect directly to my IBM buddies. It pulls pictures and other person related information right from the Domino Directory and adds locations awarness. The UI is clear and much better than the old stand-alone clients.
As far as I learned I still have to enter location information manualy and this information is stored on the client side. But I hope the design team at IBM will learn from Plazes and add a automatic location detection in the final release.
Now I am looking forward to integrate our Asterisk PBX with Sametime 7.5 to connect to the PSTN like we do it with the old Sametime environment.