Now, I previously owned a 60CS which I loved after trading in my Vista. With the newly upgraded 60CSx you get a couple of additional functions that make it much better than the 60CS. First, there's the SiRF III chipset. It is by far the best chipset out there right now. It's super sensitive and super fast. You can lock onto satellites even in your house in many cases! No longer will you loose reception in tricky situations. Most of the time you can even keep the 60CSx in your backpack and it will still track your movements.
The other highly requested function for many years is the expansion memory, now in the form of a microSD. Now you can load almost half of the U.S. into 512mb of microSD. Later, larger capacity microSD cards will be released that will allow you to loan the entire US! That's awesome!