A few answers:
Better digital LSM, simulcast and weak-signal P25 performance achieved by using a completely different receiver design. In terms of changes, this is a bigger challenge than the switch from crystals to PLL tuning.
Uses the same SMA antenna.
Range improvement for digital is hugely better than the x36s.
I believe 32G is the max SD size.
USB 2 is same as x36. USB 1, I have to check (it is currently unused).
As to NXDN, if I promise to fully address this next week, can you promise to keep this thread on the topic of the SDS100? I am only here for one more day, then have to go set up a trade show in Louisville.