A few months ago, I compared DMB and OOTP by simming the 1957 season in both games. It was not a scientific study; I know that. Yet I was pleased with the results. OOTP compared favorably to DMB in terms of statistical accuracy. I concluded (tentatively) that OOTP does better with historical replays than it gets credit for. It may also be true that DMB does not quite live up to its reputation (though it is startlingly good most of the time).
If you want to use real-life lineups and transactions, then you'll want to stick with DMB or Action. Otherwise, I think this version of OOTP has made great strides in terms of historical realism. On the beta forum, in fact, I've been pestering Markus about problems with lineups, rotations, etc., after importing a historical season. I'm glad I didn't get banned because of it!
Markus made some significant changes in the latest build. I'm pleased with the results.