The reality for teachers in my district is that many TTOC for a few years and go in and out of temporary assignments. I am thrilled to finally have converted (though part time) and be in a job share assignment currently.
I have heard of all the troubles job sharing can bring, but I have to say in my experience with job shares, there have been little to no problems.
Obviously communication is key and it helps if you and your job share partner have similar beliefs.
Currently I am in a job sharing position where I am there two days a week and she is there three. She has done eighth grade for many years and has a wealth of knowledge and resources she shares with me, but not in a forceful way.
I appreciate her ideas and feel like if I had to teach eighth grade again I would have a tonne of great units, lessons, ideas because of working with her.
Similarly, in a past job share I had two days at the end of the week so I was able to continue with her units (it was Home Ec, very new for me!)
I think job sharing is a great position for new teachers or new to a position (grade level) because it can work like mentoring in many senses.