The key differences: the screen is a bit better on the Siglent, Rigol makes you go through a stupid unlock routine to get your features, but (and this is the killer) Rigol has LXI (scriptable ethernet control) whereas the Siglent only appears to have a web-based remote control mechanism - substantially inferior IMHO.
The SDS1000X-E datasheet says that it supports SCPI over Ethernet, and there’s a programming manual available from Siglent (weirdly the links seem broken on their website)
