Infosource in BI 7.0 EPH1 - Source to BI

Are company is starting a new install of BI 7.0. We currently have a 3.5 instance as well. I have heard two different arguments when it comes to infosources in BI 7.0 from source to BI. Some people say yes use infosources and other people say no don't use infosources.

Do you know what SAP suggestions is?

Also,

Your insite would be greatly appriciated????

Thank you!

Caroline