I voted for a flexible schedule as long as it truly is flexible by your say-so. As in 40 hours a week, some nights/weekends, truly your choice when things get done. For example, you need to not work Tuesday because your child or caregiver is sick, but you can add more hours later in the week to make up for it without notifying anyone or causing a hassle.
For instance, DH has been working from home lately about 30 hours out of the week, going in maybe once a week. He's in the tech industry, and at first he was home because to do some things required for his job he kind of HAD to do it from home. Then, he found working from home allowed him to do a lot more work, so here he has been for months now. But his boss pretty much doesn't care when he works, or where he works, as long as he produces. Of course, they're like that in general -- people may wander in at 10 am or 8 am, take a two hour lunch, but then work later that night or weekend. No one really cares as long as the work is done well and on deadline. When our baby arrives, this flexibility will be of huge benefit. While I will be a SAHM, there will obviously be times I need to do something that isn't child-friendly -- doctor appointment, haircut, etc. He can easily slide his schedule around to be home, and make the work up later if he needs to.
So, if that's the kind of flexibility you're talking about, I say #2. If it's only flexible in terms of "well, we can't tell you when you'll be working, so just be available when we need you," then run away. That would be a nightmare as a parent.