Switching dynamics of ferroelectric (FE) based devices not only depend on the FE material but also on the design options available for the materials stack. However, the impact of the design of the material layers on the FE device properties is not fully understood yet. Here, we report a comprehensive characterization of Ferroelectric Tunnel Junctions based on Metal-Ferroelectric-Dielectric-Metal (MFDM) stacks and a full benchmark of the extracted parameters with those of Metal-Ferroelectric-Metal (MFM) capacitors. MFDM devices show an evident dependence of the extracted coercive voltages on the thickness of the dielectric layer (DE), as well as on the frequency of the signal used to characterize the device, which is not observed in MFM stacks. Finally, the remnant polarization measured in MFDM stacks is lower than in MFM samples. Together, all these evidences suggest that the traps at the FE-DE interface play a fundamental role in the switching dynamics of the device and in the extraction of the ferroelectric parameters.