From what I remember, Windows Mobile is more suitable for multimedia use. Palm OS is more stable. I've used Palm and Windows devices for many years and with Windows, you have the audio/video quality but soft resetting was a fact of life. Also, Windows Mobile is a memory hog.
The Moto Q is a Smartphone (won't use the same programs as Windows Mobile PDA uses), no touch screen but good for what it does as far as the price. I've had my eye on that for Sprint, but will see if the Q9 will arrive on Sprint before the SERO plans expire :)