Hired x2

I received a call, from the same company initially hiring me but this time for a different post...
I am confused...I tried explaining that I have already been offered a position already but the lady over the phone said it doesn't matter which one i choose, difference is that I will report to different manager, that's all.

I have yet to receive any directions on what to do next by my previous interviewer but for this second person, I have received all the details which include : I shall start work next monday.
Meanwhile, first interviewer mentioned that I should be working by end of this week..till now no further directions yet...maybe tomorrow..hoping so.

So now a dilemma... same company different job scope. Which one to choose? I have weighed it out...both also have 2 advantages and 2 disadvantages. But which is more important? Considering advantages as more important, it will be offer no.1 which is of my advantage. However, if I choose offer no. 1, the job is more mentally and physically draining. Arghhh... Which one? which one? decide...decide...