- Modular allows you to place a set in a city or table and still get to the interior.
- Open back allows for access on a table, but looks unfinished and out of place when seen next to fully enclosed buildings. If placed on a shelf, it forces you to pick either the front or back to display. This forces you to spin it around to see the other side, potentially a hassle depending on how tightly crammed together your display shelf is with other sets.
- Dollhouse is in a way the best of both worlds and the worst. You get a fully enclosed building which looks good on a table or shelf, but to access the inside you need either a ton of dead space on the side or to physically remove the building from wherever it is.
Overall I prefer Modular. I converted my haunted house to modular style, and at some point plan on doing the same for the Firehouse and the Simpsons house. Really hope the Wayne Mannor is modular but if not i'll convert that too.