White toilets are most commonly preferred, but most manufacturers offer a variety of hues. Before buying a color, make sure you're ready to live with that color. Let's say in a few years you desire a color change, it will be much easier to change the surrounding wall colors than to replace your toilet. You may also want to consider resale value when choosing a unique color.
Do you want to convey a look that's contemporary, traditional, casual or formal?
Styles usually don't affect the operation of the toilet, so choose a style that suits your preference.
Gravity or Pressure
Gravity-fed toilets work the old-fashioned (and most reliable) way.
Upon flushing, water is transferred from the tank into the bowl (by means of reliable gravity).
When enough water flows down into the bowl, the overwhelming volume forces everything in the bowl out through the S-shaped trap way, at which point a siphoning action takes over and finishes the job.
Pressure-assist toilets were designed to flush toilets using less water by adding compressed air to force the water into the bowl. Pressure assist toilets have a separate pressure (inner) tank within the cosmetic outer porcelain tank. The pressure assist inner tanks are completely sealed. When the inner pressure tank begins to fill with water, the trapped air inside the pressure tank gets compressed. So, when activated, the pressure-assist action pushes the water out of the tank forcefully into the bowl, effectively pushing the contents of the bowl out through the S-shaped trap. Since less water is needed in the tank, the bowl can be made larger to hold more surface water. A larger water surface usually requires less frequent cleaning. Pressure assist tank parts are not interchangeable with gravity flow tank parts. The tanks are engineered completely different.
The potential drawbacks are more than a few in our opinion. Pressure-assisted toilets are much noisier and are usually more difficult to repair than conventional gravity models. Since the pressurized tanks are installed inside a porcelain (glass) housing, and anything man made can fail, it has the potential to become extremely dangerous... Let's just say we hope no person is in the vicinity, should one malfunction. Our position has always been not to be associated with these toilets by selling them or the repair parts for them.
One-piece or two-piece
Most toilets have separate tanks and bowls that are installed by bolting them together, making them two-piece. Many higher-priced toilets are made as one-piece, have a lower profile, and are generally fancied as more stylish. Of course style is a preference. One-piece toilets tend to cost significantly more than two piece toilets because of the special engineering used in creating the flushing mechanisms.
The distance from the finished wall to the center line of the drain pipe (point where the toilet bolts connect to the floor flange) for most toilets is 12 inches. It is not uncommon to find older installations (or mistakes made during construction) which could vary between 10" - 14" inches. Manufactures in the U.S. make toilets to have a standard rough-in dimension of 12", but also make some of their models to fit 10" or 14" rough-ins. Some foreign toilets might not have a 12" rough-in, so be careful to check your room for your rough-in dimension before purchasing one.
With a seat or without a seat
Most two-piece toilets do not come with a seat. Some one-piece toilets do, but often have unique shapes or specialized bolt spread dimensions. If you buy a toilet without a seat, be careful that the toilet that you purchase does not need a unique shaped design. You will also want to pay attention to the distance between the bolts that mount the seat to the bowl of the toilet. The most common dimension for the bolt spread is 5-1/2" measured center to center. Toilet bowls with seat bolt distances other than 5-1/2" measured center to center or are uniquely shaped could present a problem in the future when you need a new seat.
Round bowl or elongated bowl
Most toilet bowls in residential installations are round; most toilet bowls used in commercial installations are elongated. The Unified Plumbing Code (UPC) developed by the International Association of Plumbing and Mechanical Officials (IAPMO) states that water closet bowls for public use shall be elongated bowls. ADA regulations also require toilet bowls to be elongated as well as 3" taller than normal toilet bowls. For residential use it really comes down to a practicality or design choice or in some cases a house structure choice. Many styles of toilets have bowls that are round but are also made in elongated versions as well; you just have to ask for them. Elongated bowls provide you with an additional two inches of space in front. This means a larger target area and usually less drip on the bowl. Toilets with elongated bowls are more expensive than round bowls but are generally preferred by men. Sometimes, room space can be a factor and a round bowl could make the difference between being able to close the bathroom door or not.