I'm hoping to save others from feeling the need to do what I did... buy both scopes to see which is the better value for money. There are a number of youtube videos out there on both scopes, but none that I found hit this handful of topics in this level of detail.

Cliff Notes:

Scope Comparison Video
Bandwidth
Rise Time
Memory Depth
USB Waveform Captures
Decode
Hantek Automatically limits Memory Depth in Serial Decode mode
Siglent still decodes when zoomed out to 1s or more
Siglent Decodes in Windowed mode
Siglent has better Decode Format / config settings

Problems / Troubleshooting
DS5072 USB doesn't work
SDO2D15 USB doesn’t work
Siglent UART Decode didn’t work
Firmware update resolved this. Most recent firmware bug fix says it fixed this is the revision notes but the problem remains.