Giant Unilamellar Vesicles (GUV) are the most commonly used biomimetic membrane model. Their production in physiological conditions through the well-known electroformation process is complex and other gel-assisted hydration procedures have recently emerged to circumvent some limitations of the process. In this work, the membrane physical properties of Giant Polymer Unilamellar Vesicles (Polymersomes) and lipid vesicles (Liposomes) obtained from the gel-assisted hydration procedure and electroformation, have been evaluated thoroughly by different techniques: micropipettes aspiration (MPA), Fluorescence Recovery After Photo Bleaching (FRAP) and Laurdan Generalized Polarization (GP). The study was performed on GUVs made of either phospholipids (POPC and DPPC) or amphiphilic copolymers based on Poly(dimethylsiloxane) and poly(ethyleneoxide). A significant deviation of stretching modulus, lateral diffusion coefficient and membrane packing was observed for GUVs formed by the PVA gel-assisted hydration method compared to the classical electroformation process. We were able to show that this deviation was due to the presence of PVA chains in the membrane and in the suspending medium. Globally our findings reveal that particular attention has to be paid on the gel assisted hydration process as the vesicles obtained present altered mechanical behaviour.