Transposed Direct Form II VS Direct Form II IIR filters?
Compared to the Direct Form I, Direct Form-II has pros and cons.


The advantage of DF-II is its more efficient usage of the delay lines. Although both use separate all-pole and all-zero sections, the DF-II can share the delay lines between them and reduce the number of required delays to implement the same transfer function.
The disadvantage of DF-II is that it precedes the poles and imposes a higher dynamic range on the intersecting delay line in some frequencies. Therefore, unlike the DF-I which first implements the zeros and is almost immune to overflow, DF-II is prone to such effects.


In the transposed DF-II the zeros are implemented first AND the delay lines are shared between the all-pole and the all-zero section. Hence, the transposed DF-II has the advantage of DF-II and also offers a better robustness similar to the behavior of DF-I.

Also, it is stated here that they are more robust when filters with a sharp-transition are implemented.