Indexing the content of files is nice when you have only a few dozen files. When you have thousands and thousands of PDF files content indexing is just a nightmare, a big cpu/memory/disk waste and does not work at all. Baloo should be completely optional and never be activated by default. Same thing for Akonadi. My only gripe with KDE is it is full of "utilities" and "features" enabled by default that produce more problems than benefits. One you disable / uninstall all of them, KDE works like a charm.
Of course it is just my opinion.
