For myself, I would choose a longer length of chain for the same weight. That's because I like to use all-chain for anchoring, when possible, so that the chain is coming right up onto the boat.

I use a long rope snubber, for shock loading, but I like knowing that there is more than "just" a rope attaching the deck cleats (or samson post, etc,) to the anchor. That's just my personal preference.

So, for example, I'd go for a longer length of 5/16" G4 (high test) chain, over a shorter length of heavier (but not stronger) 3/8" G3. (I'm not sure from your post if you are talking about G3 or G4.)

But as others have mentioned, you can't just be "close" in size on the chain gipsy. As far as I know, only in 3/8" can you even have the same gipsy for G3 and G4 of the same diameter (i.e. 5/16" G3 and 5/16" G4 take different gipsies).

Anchoring does come down to personal preference though, and this is just mine.