RLC band stop vs. RC low pass filter for switching noise in DC-DC converter
The are differences in the time response for the two filters which makes one of them unsuitable for this application. To exemplify, consider the two transfer functions:
$$\begin{align}
H_{LP}(s)&amp;=\dfrac{3}{s^2+3s+3}\tag{1} \\
H_{BS}(s)&amp;=\dfrac{s^2+9}{s^2+s+9}\tag{2}
\end{align}$$
The notch (2) has infinite attenuation at 3 rad/s, whereas the lowpass only ~0.277:

The first impression would be that the notch is superior to the lowpass when a certain bandwidth is to be attenuated. But this is frequency domain, and the power supply is considered in the time domain due to the dynamic nature of the load: there's always some variation. Which means that the time domain response is to be considered (left step, right impulse):

Note I have left aside the implicit Dirac that comes out for the impulse response of the notch filter, due to the lowpass + highpass. You certainly don't want a differentiator in the path of your supply. Most of the noise may come only from a certain range, the switching frequency, but it's not the only source, and a differentiator will amplify high frequencies. So the frequency domain is only a small part of the whole aspect.
This is why I would recommend the lowpass. Use the bandpass if you have to analyze the signal, not to filter a power supply.