SQL & PL/SQL

I have a situation where I need to maintain multiple comments per row. The same row gets copied to a history table. In this case, if I were to maintain a sepearate table for comments then I need two table of comments. Instead I am planning to use nested tables feature. I know it looks like cumbersome way to insert and update nested tables. Does anyone know what are the advantages and disadvantages using separate table vs nested tables.

thanks