The hardware is great, I eventually exchanged it for the palm OS version. However, the memory issues and constant freezing of the windows mobile OS made me miss calls and become very familiar with hard resets. You'll constantly have to go into the task manager to close applications that are still resident in the memory.The most frustrating part for me is when it decided to hang while there was an incoming call. After a 30-45 second hard boot you'll have to call them back and explain that your phone froze.After switching to the Palm OS version of this device I never had a problem. I love the windows interface, but it's just to buggy and unstable. (I could insert a snarky Microsoft comment here, but why beat that dead horse)PS... Friends have also told me that other devices they own with Windows Mobile also have stability issues. So it doesn't seem like this is isolated to the Treo.