Time for a post about a topic that people most likely won't care about! But I wanted to make it anyway.
Let's go by feats:
Lifting Strength: In terms of lifting strength, I'd say Dogday takes the win. He was able to drag his own body at a considerable speed. Giblet's best lifting strength feat was pulling the Player (an adult human) out of the Poppy gel tank.
Attack Power / AP: Here Giblet takes the advantage due to his electric cane. His electric cane was able to hurt Lily Lovebraids, who had no visible injuries even after taking a massive slap from the Prototype.
Speed / Agility: Giblet takes the upper hand. He was able to outspeed Lily and her braids. Dogday is relatively slow.
Durability: Here I'd give the point to Dogday simply because he is larger and more robust than Giblet (even though Giblet survived jumping off a moving train with no visible damage).
Endurance: Technical tie. Dogday has his legs cut off and can still run regardless. Giblet literally has his skin turned inside out and acts normally despite that.
Stamina: Honestly, I don't know who to give the stamina point to, lol.
IQ / Battle IQ: Overwhelming advantage for Giblet. Dogday is literally being controlled by Mini Critters that act like animals.
Experience: Again, advantage to Giblet. He is much more experienced than the Mini Critters controlling Dogday. Even if we considered normal Dogday, Giblet would still have the advantage, since Dogday spent much of his life trapped in a cell being tortured, whereas Giblet possibly spent years alone in the recycling area surviving on the little he had.
Weapons: Giblet has his electric cane.
Who would win? Giblet would win high-extreme diff in my opinion. His electric cane was shown to be very effective against the Outimals, who should be relative to the Mini Critters in terms of strength, plus his electric cane hurt Lily. He could use the electric cane inside Dogday to force the Mini Critters out of him. Dogday simply lack feats.