I bought this unit as an upgrade to my older 60csx. Frankly, I wish I hadn't. Yes, the 64st is a great unit. It is slightly more accurate. But: (-) It lacks the round 12V port. That means I have to use a regular USB cord when the unit is RAM mounted to my windshield. This is probably the most annoying miss. (+) On the plus side it will charge while plugged in. (-) But it only charges using their battery pack. It won't charge stand alone NiMH AA batteries. OK, it will, but not as designed and you need to bubba the device to make it charge AA cells. (-) The USB port on the back is way recessed. I bought a 90* mini-USB and it didn't work. The port was too deep. This means the USB charging cable comes straight out then has to bend down to my dash to a USB adapter in my 12V outlet. Not ideal, and I prefer the round plug used on previous units for keeping the unit running while exploring. (-) It's supposed to be more accurate since it has the ability to access more satellites. I'm not convinced. I didn't see a significant difference in accuracy putting the 60csx side by next with the 64st. Conclusion. If you are purchasing your first GPS, this will do just dandy. If you are considering upgrading from a 60xx, don't bother.