Since you currently own a Mogul, I am sure you are aware that just about everything regarding the Mogul can be located within this site... AND with that knowledge readily available you know what you have and where to find it.
However I would recommend visiting a few review sites like
www.Cnet.com,
www.engadget.com on other makes/models that interest you as well as sitting in on some of the forums related to that device. Unbiased user opinions, polls and every-day user reviews will better answer and later define the device that best suits you.
The Palm 755 I believe is available with a MW & Palm OS and the Motorola Q9 is a smartphone (non-touch pda devices are called smartphones while touch-enabled pda's are called Pocket PC's) and both offer diverse form, functions, etc from one another.