Sadly, the option to insert a date/time stamp in PPC notes has been abandoned.
(The original Windows CE had this option)
However, PHM Notepad (
www.phm.lu/products) is a nice free notepad substitute that supports single click date/time stamping.
(There are probably others)
As for Palm vs. PPC, here is a somewhat biased (toward PPC) comparision link that may be of some help to you:
http://www.cewindows.net/palm.htm