The Westinghouse designs are more efficient and contain the radioactive fluids/gasses better, but the BWR’s are cheaper to build.
Now, see, here we go. I didn’t want to go there - but yeah, I do prefer the Circle-Bar-W units. (Full disclosure - that’s a local company to me and some family have been involved in the business). The construction cost advantage does go to GE.
However, I know of at least one GE plant that had a fuel pin split and lost a couple or three pellets in the stream. That added millions to the costs on their next outage. I realized real fast why there is a bio shield around the turbine floor.