Rigol is a satisfactory machine if used properly. Its big advanatage is price, for what it is and can do its a deal
you can't even get the attention of Keysight (Hp ne Agilent now...) refurbished equipment for that kind of money.
I've seen people using HP do stupid things and claim but the machine said such and so. I've done it the hard
way for decades and every time I get a piece of gear life gets easier and I had to learn to use it correctly. Most
if not all of the measurements discussed are not hard to do and do not require exotic gear but will require patience
and knowing how to perform the measurement.
To that end a copy of EMRFD the section on tests and measurements is well worth it.