Man, I'll jump in here. Taught both. Flown with guys from both. This is a bit of over generalization because there's a lot of other things going on too besides where you learned to fly by the time you show up at a regional. I think Part 61 turns out better stick and rudder guys that can also think through and reason through stuff on their own. But 141 turns out pilots better suited for the procedural approach of sitting right seat in a regional airline and learning how to think through and reason through problems in the way their airline wants them to. Both are fine in the long run but from the left seat, I find it much easier to PF with a part 141 types and easier to PM with a part 61 types. The more time they have with the airline, the more time their prior experience doesn't matter.