Another thing worth considering....
Remember that you are auditioning them as much as they are auditioning you. That doesn't mean be egotistical.... rather, do they sound good to you, do they gel well and are you feeling that 'link' that makes you want to be part of their band? I've lost count of the number of bands I've auditioned for but ended up not wanting to part of.... either due to musical, social or practical reasons....
They have to be worth YOUR time as much as you are (hopefully) worth THEIRS.