Because Agilent it has less memory for example tektronix MDO it has 10 Mpoints, Agilent only 2 channels, math mode is limited. I work also with Resolver sensors and I want a Scope with advanced math for introdusing equations for compute angle. Siglent is great device for price, but is very slow, when you uses the Tek, agilent or fluke is great difference in response, for 500 USD, 200 MHz, 4 channels and control from Wifi more bode plot I can't ask for more, but I want a powerful scope and see a oportunity, in Mexico only found Tek scopes from WWII, 2kPoints for memory deep and 100 MHz, phosphor emulation is very strange found in second hand.
When I was student of deegre, I working for my thesis in a AC-AC converter, I used TDS3000B and MSO or MDO I don't remeber, visualization on TDS is better than more newer Tektronix in 3000 series, but TDS is very limited for actual days I think that it. The idea for Agilent Dso8064a is because it has very big memory deep and decode serial also, but I have never used one of that type, in this forum many people it has experience from cheap scopes up to very expensive, for this for that reason I ask for suggestions based on your personal experience of handling this equipment. About R&S scopes really I like it, but in Mexico is not common brand, only fluke, tek and keysight/agilent you can get for good price.
Regards.