Hi Gaye;
I spoke to our internal RMK expert and he said this which makes sense to me. With the differences below, I would say the customer has so much more work and risk as SF will not support anything that is configured outside the SF system.
Hosted: All the pages (Career home page and featured pages) are hosted by SuccessFactors. When applicants click on career link on the corporate site, it will re-direct them to SF pages.
Integrated: Some customers try to manage the Career home page internally. In that case they can take the integrated approach. In this scenario, SF can provide code for different widgets which customer can include on their corporate career page. This is generally done if customer has already put in considerable expense on their career portal OR if they want to have tight control over the content & changes. Effort on the customer end is more with this.