I have used Treo 180 before. And the by far beats any other PDA phone I came across - O2 Atom may be an exception. I am using XDA II mini for 8 months now it is value for money.
The phone s good. Speed dial is provided.
Switching to speaker mode - no button on touch screen. You need to hold the call button for 3 sec.
The stereo headset is good quality to listen to music. And there is a volume controller and phone answer button.
Bluetooth connectivity - I had difficulties. Still have. It worked well for 2 months. I lost the settings in my PC and afterwards I found it difficult for a while, but it is up and running now. Caution : Bluetooth sync, if left turned on, consumes a lot of battery.
GPRS - good. You can browse any web page using WAP or GPRS.
You can have IMAP4 and POP3 client receiving mails through GPRS - It works very well. I also tried running IRC clients and messengers - they work fine. Speed depends on your service provider.
Only issue is once you gets disconnected from GPRS to connect again, you need to restart the network connection. I checked with my service provider - AirTel. They suggest restarting the phone after a connection drop for any phone - it is not that drastic. Turning network on and off will do.
Another improvement area - it is not easy to turn off phone alone. You need to use the stylus for that. Same with turning on the silent mode.
With PocketMusic (freeware) you get all winamp functionalities, if you do not like Windows media player. Another freeware PocketTV can play VCDs copied to your SD card.
If Microsoft voice command was available in India you could have used this device hands free. I have tried the trial version. But it is not available for sale outside US, Cananda and Europe.
No hangs ever experienced as mentioned for XDA.
Overall it is excellent.