And regarding DHO1k hacking.. I think unless you get a spare ADC everything is squeezed out of the DHO1k until now..
And it looks like DHO1k is phasing out? So maybe it will be dropped from rigol? DHO800 will be a better "cash cow"?
The recent hacking approach (patching some "which functions are supported here?" calls in the Auklet Android app) has been able to unlock the 50 Ohm inputs and other features normally reserved for the DHO4000, without the unwanted side effects of assuming the dual-ADC configuration of the 4000.
There is some speculation that the original DHO1000 series might be phased out, based on the large discounts currently offered. But reassuringly, the DHO4000 as well as the DHO120xU (recently introduced in China) share the same firmware. So I would hope that future maintenance/upgrade releases will be made available for the DHO1000 tooo, even if it should be discontinued.
Two points pro DHO1K are the 14/16bit mode which the DHO800 not has?
And the 10MHz ref in is nice to be used with my GPSDO but would this be a big advantage?? I don't know.. on the MSO5k it would probably more helpfull..?
If you want to use the DHO as your "precision scope", the 10 MHz reference might make sense. The 14/16 bit modes (with significantly reduced bandwidth) certainly do.
There are various additional aspects where the 1000 series is ahead of the 800/900; whether they are important to you, only you can decide: Separate EXT trigger input, 200 MHz usable in 4-channel mode (at 500 MSa/s per channel), higher waveform update rate, faster boot time, automated measurements in cursor-defined regions...
For me personally, the larger form factor is an important argument in favor of the 1000. It is not just the absolute screen size, but also its higher resolution which leaves more spave for "net content". For my taste, the relatively large control elements and window frames leave too little room for trace display on the DHO800. Also, I prefer the built-in power supply, but realize that others might see the external USB-C power as an advantage.