How old are the children? I know folks with older kids that find this an effective arrangement. I don't think it's good for the younger set, though.
Can he and does he schedule his travel around the kids' schedule? If not, I wouldn't do the 50/50 because you cannot be counted on him to take his week and you will likely be picking up the slack.
My ex traveled a great deal, so I got primary physical and joint legal AND he had to give me a minimum of 48 hours' notice when he could not take his parenting time. Perhaps something like that is helpful to you.
If he's not a bad father, why the evaluation?