Answer 1

Both are good for different applications.

SQL compliant solutions are well organized, array or matrix-like, which provides data conformity and integrity. It gets pretty heavy though, even for relatively sparse datasets, as tables are always "column-wide" for all rows, whether a particular cell contains data or not.

NoSQL solutions are more flexible, as they work on a different logic. Each entry may contain different type of data, of different length, size or format. Memory-wise, it grows only to the size of its data. A mechanism inside it keeps control of data integrity.