Splitting Up

So, the partners at the law firm I work for have decided to split up (amicably) and the world has wrought many decisions into my life now, specifically as they have decided that the administrative staff (me and the office manager) should be left to our own choice. Should I stay with Partner A or Partner B, should I try to look for another job (I have made faint attempts, and even been interviewed, and getting the oh so unsatisfying reply that "You were our second choice") or should I just flip a coin? I know for a fact I am underpaid, however I have had flexible hours and a family friendly environment, so I am torn between the comfortable and the unknown, the pressures and the flexibilities...at the moment I am in freefall, and I think I know where it will end up--just not sure if that is where I want to be.