Say no more.
Life is short.
I would advise the lower paying but pleasant job, over the higher paying but toxic job, always.
As someone who just did the job hunt thing a year ago and made a major move, I can tell you that many, many jobs pay enough. Don't torture yourself to make $550K instead of $450K. Just don't. The marginal utility of the extra $60K post tax isn't as great as you think. JMHO, of course.
Almost all jobs pay enough, but not all jobs are tolerable, much less enjoyable. The #1 thing that makes any place good or bad are the people there, and a close #2 is how brutal/frequent the call is. Sounds like your OB job offer is 0 for 2 there ...
Also, agree with everyone else who said that new grads should go to a diverse practice. (Excepting those that are peds/CT/pain/CCM fellowship trained who want to be pigeonholed in those subspecialties - there will always be places they can go later to do the same. OB-only jobs are scarce.) A generalist who goes to an OB-only practice for a few years is going to be in an awkward state when the hospital burns down, or the group implodes, or the spouse demands a move to a different city, or it gets to be too much and you just can't take it any more.
It's rare for a first job to be your only job. Taking that job might close some doors a few years later.