Hello!
I personally prefer SDS3000xHD.
In short, SDS3000xHD is more advanced in analysis features.
It has measurements with statistics and histicons. Trend and track plots.
Advanced arbitrary formula math. Good FFT.
Bode plot would not only work with sdg6052X, but works completely plug and play and. Make note Bode plot is multichannel.
SDS3000xHD is also MSO. That means it is actually 4 analog + 16 digital scope. Etc.etc.
Better DC accuracy. Very large input offset ranges.
Truth is, if you only use scope for "only looking at the waveforms", both scopes will do.
If you want to know which scope is more advanced measurement instrument, that is SDS3000xHD.
Also, SDS3000xHD is still in active development where all kinds of features are being added to the platform.
DHO4000 haven't seen much development in 2 years AFAIK. Rigol is also not famous for good FW debug process. I don't know but I would presume that in 2 years at least critical bugs were ironed out by now, though.
Since both are not exactly pocket money, I would recommend trying them if you can...