I want to highlight changes which are introduced by myself in the pdf document. So far the soul package is very neat but it does throw errors when I want to highlight not only paragraphs but also some itemize environments, and I don't want to highlight the items separately. Also the \cite{...} command is not supported by \hl. I recently posted a slightly different question: Change text background within paragraph (with automatic linebreaks)
BTW: What I liked most over other approaches like pdfcomments etc. is that the \hl command from soul has a very exact and clear output, no icons, no clicking etc. involved. Together with todonotes it's very good and almost all I need.
