On the welectron page, you can sort explicit by bestsellers.
But it makes less sense as they only sell siglent scopes..
And it´s no surprise that the cheaper models are on top.
What rigol concerns I have no doubt about it, that the DS1000Z series are the most selling ones on the planet.
Under hobbyists.
Afaik it was the first cheap AND usable 4-ch scope, this you can´t beat normally even when other brands models do some things better.
Same with the MSO5000 from rigol what features and samplerate/memory concerns.
Same with the RTB2000 from R&S, as the first "cheap" hi-res scope.
When you can choose between models with nearly the same price, you will choose the "better" one (for you).
Otherwise the price itself will decide.
So it won´t be a surprise when the forthcoming rigol hdo1000 will be selling better than the hdo 4000 or the siglent sds2000hd.