From some source I have heard that the other one is informal.
I am considering using this word in the IELTS Academic writing, particularly in the following sentence.
Overall, both sites offer almost equal extent of accessibility from a city centre, although each of them has its own advantages over the other one.
Is this appropriate to use these structures in this type of an essay?
Research conducted before asking:
1. A Google search ("the other one" formal, "the other one" informal, what is informal in ielts essay) gave no relevant answers.
2. SkELL's British corpus has entries of structures "the %word% one".