Assuming they have the same features, it comes down to individual preference. Both the Bravo and Element are considered "chassises" because of how they interface with the action. "Stocks" generally refer to anything that uses a traditional wood, polymer, or fiberglass interface with the action (even if it uses pillars). There are hybrids as well like Manners's mini-chassis.
I like to shoot with my thumb "up" rather than wrapped behind a pistol grip, so the KRG chassis or MPA Matrix feel better to me.
I would highly recommend something that has at a minimum adjustable cheek height and length of pull. I also like to be able to adjust buttpad height to get my shoulder behind the bore. KRG has an inexpensive upgrade for the Bravo that works well for me: https://kineticresearchgroup.com/product/tool-less-pad/