Quite happy. I have used Nokia 6210 connected with a USB cable, and also Sony Ericsson K610i through Bluetooth. The only problem I have had is battery life while connected on 3G, but I resolved this quite easily by putting them on a USB charger (a retractable one with various different tips that I travel around with). The Nokia has a separate USB data connection and a charging port.

I have not had a call come in while I was online on the Nokia but I was surprised that K610i coped very well with me being online and taking a call at the same time.

By the way I don't know if these phones are available in the US - I'm in Europe/Australia.