Generally, if you need a lot of structure in order to get the job done, go 141. If you can motivate yourself to do it, then 61 is the thing to do.

I'm not sure it makes a big difference at the PPL level though. It may be more relevant for the IFR and the CPL.

You want to be the best pilot you can be. In my mind, it doesn't matter if you go 61 or 141. All else being equal, get a good instructor and all will be well.