The two main advantages of the Hx4 over the X4 are:
- "an ethernet port allow users to add the device to their networks, meaning the Hx4 can be reprogrammed from a remote location."
- it can now be programmed directly from a Mac
If that's worth $500 to you then yes I would go ahead and get the Hx4! But then I would also look at the FX4 which is only a few hundred dollars more and offers a lot more in my opinion!