You say "I dont like using the ones on the cell phones because if u get a call it interfers with using the gps." That isn't true if you don't enable the hands-free feature on these devices.
IF you need/want custom POI support, there are still a very few GO 620 devices available (TomTom store at Amazon). Those are the last that support that feature.
The most recent devices are a lot faster (in all respects) than the older ones. Apart from voice command (which almost never false enables these days!) what features are important to you?
Here is a comparo chart for the current stable of devices. The Supreme and Discover both offer voice control:
Find out everything about TomTom's latest GPS navigation devices for cars. With latest maps, live traffic, speed camera, and more.
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On the Discover, the "New Live Services" includes things like fuel prices (very accurate here in the U.S. - I think they get them from Gas Buddy), live parking info for some cities, and some weather at destination info. If you want to know the price for regular unleaded at the Murphy's at Citi Centre and 17, you just pan over, zoom up, and there it is. The Discover also comes with a 7" screen. Nice for aging eyes.
I prefer to connect them for traffic & etc. using my phone as a WiFi hotspot. Seems to be a very reliable solution. Bluetooth tethering also works for that purpose on Android, but not always predictably on iPhones. I wish Apple wasn't still trying to create/support their own Bluetooth stacks. Too proud to buy it from companies who have been in that business since the beginning, I guess.