The quote from Handspring:

"...Cingular-branded Treo 600s have been optimized for use on the Cingular Wireless network. Customers who use Cingular-branded Treo 600s on other GSM/GPRS network may not receive optimal voice reception or data speed..."

Does anyone have any idea what is behind this quote? Like many other people I am looking at the option of getting a Cingular Treo 600 for use on T-Mobile. The only information I could find was one post claiming the data rate was 10Kbps slower. Plus many people who say the phone seems to work fine on T-Mobile.

Any hard facts out there?