Whelp, these are dangerous waters for a first post! I've read this and the related threads with great interest.
I'm very interested in comparison of the Siglent 1104x-e v. Rigol 1000z options v. Micsig TO1104 head to head. I wonder if the DS1074Z Plus or DS1074Z-S Plus might be the best deals on the Rigol side right now? Those are the configurations that support the MSO upgrade and also have function generation, respectively. (My understanding is that the Rigol function generator is a factory hardware option, as is the presence of the port for the MSO harness.) Presuming the Riglol hacks, the Siglent plus the external signal generator is within $50 of the DS1074Z-S Plus hacked to full BW (Amazon pricing).
I'd also be interested in comparison to a Keysight DSO1024A as a reference, which can be found used w/a limited warranty for around $800 after S/H, tax etc in the US right now. And I suppose at that point, the Siglent 11204x-e as well which is around the same price from Saelig. Perhaps that's the best absolute value if one's budget can stretch? All of these choices are within reasonable reach of the others, although dongles like the Siglent generator can be purchased later to spread out the cost, and of course adding Keysight options is prohibitively expensive.
Possibly there's a practical advantage for rank beginners with Keysight in that a lot of downloadable course material contains procedures for either Agilent/Keysight or Tek control panels & menus. And along the same lines, there might be a practical advantage for the Micsig is that it makes automotive tinkering or field use much more inviting. The latter being interesting to me as an inactive ham operator looking to get into back into that hobby with mobile SDR and embedded IOT radio stuff.
I guess there's the Instek too, but at a glance it seems to offer less overall. Possibly I'm being suckered by shiny things and community enthusiasm for Rigol and Siglent as a newbie. I haven't looked further.
A final thought: might the current Rigol promotion suggest a new series is coming after March? (But if so, it probably won't be as hackable, one would expect.)