I bought an iQue...
...but haven't used it on the bike yet.
I have an Otterbox on order, and intend to mount it on the handlebars.
I have used it in the car so will be used to it by the time I use it on the bike. It is very well made, but the voice instructions are not good enough for you to carry it in your pocket - you need to be able to see the screen.
The iQue still has the problem that I believe has been cured on the StreetPilot etc - it doesn't understand roundabouts. It tells you to turn left when you enter a roundabout regardless of which exit you are taking. I am told that this will be fixed in a patch in about 4 weeks time.
If you want a reliable PDA that will guide you to your Outlook contact's address and also be a weekend GPS for your bike, from my experience so far it is very good. For more serious stuff, maybe you should go for a StreetPilot.
btw, I tried an iPAQ/Bluetooth/CoPilot live first. Sent it back - HP Bluetooth is very unstable and made the package totally unusable and sorting out where the problem lay was a nightmare. With the iQue if you have a problem, you only have to call Garmin.
and long 
