If you are talking about MBB I would always go for better cultural fit. I think there is very little difference between top consulting firms elsewhere. My impression is that the culture will depend also in the office to which you are applying.
To be honest I think very few people will have to make that choice given how low offer rates are at these firms. If you have the priviledge of getting offers from more than one MBB then I would suggest talking directly to people at these firms to get some insider tips.
In terms of reputation I don't see that much difference amongst MBB.