As for the DS1054Z vs the SDS1104X-E, I have them both. They both work fine, especially at their price points, but neither is perfect.
This.
Dismiss any idea that the Siglent is "perfect", it has issues too.
The only quirk I worry about is that the Rigol has some issues about what it is actually displaying and how it is interpolating that I don't understand--this has been discussed elsewhere.
It's not difficult to understand it's just that the Rigol-hater-club that inhabits this forum tries to exaggerate it beyond all reason and the details get lost.
Some oscilloscopes have the option to turn off sin(x)/x signal reconstruction. Not all of them do (most expensive ones don't!) because it makes no sense to do so. It's a fundamental part of signal reconstruction and drawing the wiggly lines on screen.
The Rigol does have it but it only appears when you turn on more than two channels enabled and it's sampling at 250Mhz. It's greyed out at all other times because the sample rate isn't anywhere near the Nyquist limit so sin(x)/x is the correct thing to do.
What the Rigol-hater club discovered is that when you turn sin(x)/x "Off", it doesn't really turn off. Instead it changes to a "Rigol interpolation".
We don't know the exact math of this interpolation, hence the FUD. The only 'issue' is that it's not what the OCD types think "sin(x)/x turned off" ought to be.
(note: Nowhere is it written what "sin(x)/x turned off"
should be, it's undefined, it's an error condition...)
OTOH we can see that Rigols' mystery interpolation reduces the Gibbs Phenomenon when you're on the limit, ie. it's
better than sin(x)/x when you're on the Nyquist limit.