DS1000Z is entry level multipurpose toy what is not good in anything.
SDS1000X is strong entry level oscilloscope (but only 2 channel + ext trig) with some totally unbeated oscilloscope functions in its price class.
Sorry to reorder the quote, and emphasis from me. But, seriously?
Edit: More emphasis on silly statements.
Semi seriously.
Rigol problem is high noise level, very poor sin(x)/x joke (explained here in forum several times and leads example to wrong levels). Trigger and delay time jitter quite high, possible origin partially from signal noise and partially poor clock aand perhaps also trigger position fine adjust iterpolation is poor. Slow UI. Poor user interface ergonomy including shared vertical control and small display. Poor intensity grading. Lack of true seqmented memory acguisition. Lack of always bacround working waveform history. (just some kind of quite slow frame recorder). Very unprofessional mask test what give very easy statistical random error in test result. (due to very different speed if mask test pass or fail). 1mV and 2mV/div are not true analog sensitivity.
SDS1000X
max 60kwfm/s average, max >400kwfm/s (quaranteed speed, not average or peak speed) in sequence (segmented memory)
Full speed hardware based mask test.
Always in backround continuous history recording up to 80000 last captured single waveforms. (stop and look what just previously happend)
Down to 500uV/div full bandwidth true analog sensitivity low noise front end.
Inputs 1Mohm / 50ohm.
Separate vertical adjustments for channels.
Sin(x)/x and line modes, both always draw trace via true raw sample points what are not flushed to toilet as Rigol do (starting from beginning with DS1052E, Rigol have this same joke where they flush out true data and supersede it with "fake nice draw using" (imho its betteer name is "smooth").
I have used both. I have also purchased DS1000Z for one my project where need cheap scope standing alone collecting data including fact that if poor luck it can also damage. So I select this because it was cheap and have four channel. But, later I see it was wrong selection. All data nearly like from garbage generator due to noise and trig jitter.
But, for many hobbyist, even if it is toy, it have lot of "things" and for many use - I did not say it is useless. If look how many features get with quite low price.... well, and if need cheap kitchen all in one multipurpose toy what can do tens of miracles but nothing well (we know these kitchen machines). This is like same, lot of things, it can do many things but nothing well. And many peoples buy.
Toy is not here as synonym for unusable.