GAT-X303 Aegis Gundam - Only had the problem of its limited power supply. Bring it back and give it a nuclear engine and asses will be whopped.
ZGMF-X09A Justice Gundam- Good Gundam but the Aegis was better. Liked that pose when he connected his beamsabers.
ZGMF-X23S Saviour Gundam - Now this gundam would've become my favorite but Kira had to be an ass and destroy it. So much potential wasted.
ZGMF-X19A Infinite Justice- This suit may become my new favorite. I like its arsenal of beam weaponry.

I can't make a definite choice yet but for now I will choose the ZGMF-X23S Saviour Gundam.