The Cardinal's current design is fairly stock. One plain color with the logo featured in a medium size. It's not bad, but there's a lot of room for creative improvement. The artist's designs are mainly just resizings of the cardinal logo, but that's not a bad thing, even if it is the most direct creative route.
The top right and the bottom left take two different approaches to the giant sized cardinal head. I tend to like that type of design when the mascot's eyes are big and prominent like they are here. The bottom right is likely to attract more old school fans since it is similar to the old logo with some added features, like the split color top and bottom. The silver is a nice touch as well, but in this case, these new designs make the old one look good.