Biggest difference is that the older Pulse (black) hub connects to C4 via RS232 / serial port while Pulse 2 (white) hub connects via IP. This is huge as it gives you a lot more flexibility in terms of where you can place the hub (ideally centrally to all the shades you are controlling).
Also, Pulse 2 can do sunset / sunrise based scheduling directly via the Rollease app, which I don't think the old Pulse hub could (it could only do it based on absolute time).
I also think the Pulse 2 app now supports iPad natively.
Here is a detailed comparison https://www.rolleaseacmeda.com/docs/default-source/us/automate-controllers/automate-pulse-2/automate_hub_comparison.pdf?sfvrsn=f246ea3c_8
If I were you, I would get your dealer to give you the latest Pulse 2 hub - no point in getting older hardware.