We've used the Siglent Bode function often, and have also reported it's slow, real slow (we are not a fanboy)!! With this in mind it does give superb results as mentioned by 2N3055, slow yes, but accurate with a very wide dynamic range if utilized properly by someone that understands how the Bode function operates within the DSO.
If getting the correct, accurate answers is important, one can often overlook the speed!!
Now you make it sound like slow = accurate but that simply isn't true. The results from R&S's implementation (the one I have experience with but I don't see why others should be different) are just as accurate. So they deliver the same answer in less time. I have repeated several of the measurements you have shown using my R&S oscilloscope and got to the same results.
He never said slow was accurate.. He said (same as I did) it is dead accurate but somewhat slower then R&S and Keysight... And it is not seconds to hours difference...
And it is debatable if you got exactly the same result. You don't have a Siglent scope to really set it up the same... It looks OK though, and we said that.
Again, against what sub 1000 USD scope you are comparing Siglent SDS1104X-E bode plot feature/speed/accuracy set?
How many scopes (at any price range) can perform bode plot analysis of a 3-way active xover (low, mid, hi) at the same time on the same screen.
How long does it take to do that on Keysight or R&S..
I did check against the Keysight 3000T and got better dynamic range with Siglents I have..
Is that because I'm comparing a 500uV/div 12 bit scope against 8 bit scope with 4mV/div with more noise ??
That could be the case.... But the both SDS6000 and SDS2000X HD had better dynamic range than MSOX3104T...
For general use both will be good enough to gather -3dB point frequency, general shape of curves, etc..
There is also one more thing that were discussing. It is much easier to measure filters (passive and active) in quiet environment, than loop response of switching PSU with aggressor signals being orders or magnitude larger.
With switching PSU, ability of BODE plotter (whatever it is) to extract phase/gain of stimulus is very much a question of extracting very small signal from switcher natural output ripple.
In which case frequency selective detector and averagning helps a lot.. In which case slower is better....
So yeah, it is MUCH more complicated than: SLOW!!!! BAD!!!!!