Crotch – Best Practice

Is there something that would be considered as the best practice to draw the “crotch”? Are there any pros and cons for choosing one of these (or other) approaches:

I usually go for the fourth example, but I would love to hear arguments for choosing the other variants. Especially if someone has experience with different performance in engraving, foil cutting, modeling, 3D printing etc.

Either third or forth. There were rendering problems with sharp corners a long time ago.