Even with it's WAP limitations, the Blazer browser on a Palm OS device is superior to Internet Explorer on a Windows Mobile device. Screen resolution and the quality of page rendering come to mind… And, the requirement to have to reconnect after an idle time of 20 to 30 seconds is annoying, and if it happens often enough, completely eliminates the speed advantage of the Internet Explorer.
On the other hand, the Verizon-provided Treo 700w uses the network's EVDO broadband link to browse, offering a huge speed advantage. Ah, but that idle time issue…
Future releases of the Treo family for Palm and possibly Linux are expected to take advantage of 'mobile broadband' provisioning like EVDO. Palm has announced that it will deliver four Treo devices in 2006, and only one is likely to be a Windows Mobile device.
No Windows Mobile device of any kind is supported by iSync directly. You'll need to use a third party application from Mark/Space or Information Appliance Associates. Both companies offers products—the Missing Sync for Windows Mobile and PocketMac—which support Windows Mobile devices, but neither support Windows Mobile 5 yet. Both companies have promised free, near term releases of their current applications to support units like the Treo 700w.
Given the near term release of additional Treo models, I would tend to wait to see what happens in the next sixty to ninety days before purchasing a Treo. And, given the current situation, you have to want to use Verizon as a carrier, though future Palm OS devices are likely to be offered by Cingular [or ATT, as they are soon to be known as again] and T-Mobile, in addition to Verizon in the US.