Depends n your definition of “better”
They both have a reasonably full range of tools and functions - what you do with them depends on your skill and knowledge of them. I and many others prefer Hex for its ease and simplicity, but that could be because of personal preference and familiarity.
Hex is inclined to be pretty quirky and unforgiving of user error, whilst Carrara is pretty much rock-solid.
Hex has the Studio bridge, making it a lot easier to create morphs and content. So, basically, it comes down to want you need the applications for.