I've been doing this for a few years. The key to getting the right texture is taking the pork butt a little past your normal finishing temp, I usually take mine to 210°, to get the softer 'mushy' feel, doing this helps them hold together better when smashing.
Pop one on a toasted bun with some pepperjack, pickled onions, bread and butter pickles, and some spicy bbq sauce....that's some good eating!