[Queli]

This one is very confusing to me--if you have a class of items that you know exists but you are talking about it in the abstract (i.e. not talking about specific examples of this class), do you use subjunctive? In other words--

Prefiero libros en los que hay personajes fuertes.
o
Prefiero libros en los que haya personajes fuertes.

Siempre elige hoteles que no cobran por el uso de Internet.
o
Siempre elige hoteles que no cobren por el uso de Internet.

There are actual elements in each class, so it's not hypothetical in one sense--but you are not concerned with any specific example so it is hypothetical in another sense. And I have seen examples with both moods so I know I'm not the only one confused!

Thanks in advance for any insight.