To be honest, only scope in less than 7000-8000 € range that has something resembling realtime SA is GW-Instek MDO-2000A series.
And that is because it literally has realtime SA mode implemented. It works well but it's ADC are only 8 bit so limited dynamic range. Also scopes are in 1500€ ranges, a bit old fashioned by now etc.....
All other scopes in that price range will have only FFT as a math function, with implementation variations.
Short version for the two scopes mentioned:
- if you want just something bouncing on the screen to see if there is something happening at some frequency, DHO800 will have faster refresh at some settings.
- if you want control of what are you measuring, accurate windows, accurate level measurements, Peak Hold and Averaging, various markers and peek markers and control of them, then SDS800xHD is the one.
If you want SA display on your scope that resembles R&S MXO4 or MXO5 or Tektronix MSO 6 digital down conversion tech, you will have to pay for those...