Well to start with activesync backup is
free compared to Sprite's pocketbackup. That's about the only good thing about it though.
Whilst it is satisfactory if you only have PIM data on your pocketpc the moment you have more than a couple of MBS of data (e.g. programs) you'll notice how slow it is. 30 seconds compared to an hour is a LOT of time.

Restores are just as slow.
The other thing is I'm not sure activesync backs up all your registry settings. I've noticed that I have to re-register various programs after an activesync restore whilst this is not the case with sprite's program.
Not sure if the IPAQ you're using comes with a toned down version of Sprite's backup built in though :P