Why are T-Filters better than L-Filters?
With a high impedance measurement device on the output, both filters will be identical in performance. However, if the output of the T filter were loaded with maybe a resistor, the filter would tend to change from a 2nd order low pass filter to a 3rd order low pass filter. If the resistor were swapped for another capacitor then the filter would tend to become a 4th order filter.

As to exact frequency response this cannot be determined without values.