I typically do what SteveP does too, using the Lahman db with few minors (I usually only use AAA which pretty much functions as a reserve squad with recalc on).
I unfortunately don't have any experience with the other DBs. I've never had problems with guys getting stuck in the minors, but I have had problems with guys having to share ABs or IPs. I had a solo league where the 61 Giants traded for Robin Roberts and somebody else (I forget who) and pushed Jack Sanford and Juan Marichal to the bullpen despite the fact that they were perfectly good starters. I subsequently traded for Sanford at a discount, but that is another story
I also don't draft usually either - I prefer my players to end up where they are 'supposed' to. It could be when you draft the players, there could be clogs in the system they end up in, like Clemente is stuck behind Roger Maris or another hot performing player. Or like the situation I described where the AI acquires too many SPs.