The biggest pro of stacked units is their compact size. They're about the same price as middle-of-the-road top-loaders and cost considerably less than front- loaders. They're ideal for apartment or condo living, or if you're short on space for a dedicated laundry area. They're generally quieter than side-by-side models and use electricity rather than gas, which means you don't need to vent your dryer. Keep in mind, though, that electric dryers will cost you more to run than gas. They do, however, require a 240-volt outlet (regular outlets produce 120 volts), so this probably means hiring an electrician to install one. The load-sizes in these all-in-one stackable units tend to be a little smaller, though you can find units that compare to a standard top-loader. Another consideration is your height. If you happen to be vertically challenged, you may not be too hip on using a stepping stool to empty your dryer. If you've got some space to work with in your laundry area, but you're really not sure how you want your new units arranged, front-loaders offer the best of both worlds because certain models are designed to be stacked. Bottom line, you get your XL high-efficiency machine in a compact setup.