I too have been flipping back and forth between the two games trying to find the better historical sim (which is 100% the way I play these games). Ive been finding myself coming back to OOTP more, only because in PureSim, in order to have an initial inaugrial draft with historical players you have to rename all of the teams in the league from fictional names and cities, and that drives me insane. If you could do an initial draft from the other mode (historical career I think it is ?) that would be awesome.
Ive also found that the super scrubs are still WAY better than they should be. In my last Puresim 1903 test, the top 8 OPS players were fictional players that should have been "superscrubs". One of them had 88 HR's

With the player creation modifiers, I think OOTP's fictional players come out much worse (which is good). They are a little easier to manager in PS though, if you add the "year" extension to the name of real players. Superscrubs dont get a year, so they are easy to spot to edit.
All in all I havent tested PS all that much because I keep coming back to OOTP. I wish fictional players in a RL league had a * either before or after teh name, so they more easy to spot. There are enough players in history I dont know, so to have to look up, say, Jimmy Jones in 1964 to see if he is a real player or not is a pain in the butt.
OOTP deadball fielding averages are way to high also. Ive been tinkering with the engine file fielding error frequencies and throwing error frequencies trying to find a good setting for deadball errors.