IoC containers

Hi,

I am interested in hearing some first hand experience with IoC containers. So far my knowledge is only theoretical (i.e. what I read in articles) and I would like to find out how does it work in practice.

What are typical, real life (i.e. not text book) examples for IoC?
To what extent do you use the container (only for high level abstractions, or for low level as well)?
What are the downsides of this approach?

Feel free to add any additional comment about your experience with IoC not covered with these questions.

Thanks in advance.

Regards,
Sasa
.