FYI The MDO software exists as a demo app on the entire XXX-2000 line. It needs a built in AWG to start. But if you've got that, then the lower right corner button by the screen will take you out of the demo into the menu where you can control the software. You can see a bunch of examples in recent posts I made to the FeelTech FY-6600 thread along with Instek FFT plots and R&S SA plots. It's limited to 500 MHz because that's the Nyquist frequency for 1 GSa/S. It's pure FFT SA.
The SA function in the MDO line is only suitable for educational lab exercises. It's better than nothing, but you can do better simply by dumping 10 Mpts of data to a PC and using Octave to compute the spectrum.
I have an MSO-2204EA. I considered an MDO-2204EG, but decided that the LA facility was more important. Ironicly Instek called my attention to the SA demo and a bit of button mashing gave me control. It's reasonably useful up to about 10 MHz. Above that the RBW gets too large. I have urged Instek to include the software in the MSO series, but they just introduced the MDO line a few months ago. So instead of selling a standout, they're shooting themselves in the foot by making buyers choose among the GDS, MDO & MSO lines which are all the same HW with different marketing emphases.
The Instek works fairly well, but the UI is absolutely maddening and has crashed several times in a month. I bought a Siglent SA which I eventually returned because of the UI. So I spent a great deal of time reading manuals for a scope purchase. Instek had the best manual at the low end, so I bought that. Unfortunately, the manual doesn't accurately describe the scope operation. But it does have a good FFT which the Rigol does not. So I kept it. I have a VNWA 3EC on order. Not sure if I'll buy a separate SA or not. The VNWA will serve up to 1.3 GHz.