I voted soft shell.
I do like some hard shell tacos, particularly the cheap 2x$1 tacos at Jack in the Box... I don't consider them real Mexican food, but they are a tasty treat.
One of my favorite Mexican restaurants back in CA about 15 miles from the border served tacos that were in between hard and soft, meaning they weren't really soft but weren't crunchy either, but they were really tasty. That was one of my favorite mexican restaurants of all time.
Here it is. Haha, got a 1 star rating for food being greasy and bad service. I thought all the GOOD TASTING hole-in-the-wall Mexican food places have greasy food and bad service.
My favorite of course are soft tacos, and I'm not talking about stuff from Taco Bell. I'm talking "real" tacos with two soft corn tortillas, your choice of meat (such as steak, chorizo, carnitas, pastor), chopped onions, cilantro and plenty of salsa muy picante.