What if somebody feeds in a 250MHz signal into a Siglent by mistake?
Then they've made a mistake and will get mistaken results. This has little to do with the fact that the Siglent is the better scope, regardless what errors are made.
Seems like a pointless discussion anyway. Like splitting hairs. Some people like Rigol, some like Siglent and when they are as close as these two, that's probably going to be the deciding factor.
If you were discussing look and feel I would agree. If someone says "I understand SDS800xHD has better math but I don't care for that I like that DHO800 has HDMI out" who am I to argue. People know their priorities.
And I did say, on the record, that I do think that DHO800 is potentially nice little 100MHz entry level scope. I think it is buggy as hell and limited, but some people choose to live with bugs and don't need anything more than basic. And hope is (I'm sceptical at this point, but not important) Rigol will eventually iron it out to point of being rid of obvious bugs.
But facts are facts and DHO900 is hardware that is a shame of Rigol and should not have left prototype phase. It is a 250MHz scope (claimed) that in worst case samples at 156MSps/s which is FINRSI type of specmanship.
And since many people hack their DHO800 to 900 that defect is applicable to 800 too.
And then they say it is same as SDS800xHD.
It is not.
SDS800xHD is properly, professionally designed scope.
It is serious instrument.
And then there are people here that try to rewrite science to make complete lies and nonsense true because Rigol must be best... Even if it is a lie.