When buying a faucet there are a few things you should be asking yourself:

Is it easy to get parts?
Easy to repair and replace parts?
Where is it made?
What type of warranty?
How long has this model been made?
Does the manufacturer stand behind their products and how long has that company been in business?
Is the company that you are buying the faucet from reputable and been in business long enough so that you know you can trust them?

Also consider:

Cost:

Some faucets are simply made better than others with higher quality material such as solid brass, which generally provides a superior look, performance, and durability. While you may pay more for a quality faucet, you're likely to receive more value for your money as a result of longer, more reliable, trouble-free service. Paying more doesn't always mean you'll get a better value, but generally, a more expensive faucet (just like a more expensive automobile, etc) does give better and longer service. We recommend that you DO shop around once you know the exact brand and model that you want, as you can avoid paying extra for the exact same faucets if you spend time to shop. Or save time and money by buying from us right away instead of after a few hours of searching - our prices are very low and that is because of our low overhead and the fact that we have been doing this for so long.

Sizing:

Standard size sink openings and faucet dimensions are used throughout the U.S. plumbing industry. Sometimes, when mixing a foreign made faucet or sink there could be a problem (although rare). Generally, the standard distance between hot and cold inlets or the mounting hardware for both single and two-handle kitchen model faucets is 8" from center to center and 4" from center to center for bathroom (lavatory) faucets. However, because there are a few exceptions, it is always a good idea to check sizes first before placing your order.

Also, there are widespread faucets and centerset faucets. A widespread faucet includes three separate parts that measure from 8 to 16 inches from center to center. A mini-widespread is much like a widespread but can mount 4 inches from center to center. The difference between a widespread and a centerset faucet is that widespread faucets have adjustable centers due to flex hoses, while centerset faucets do not. From the image shown below, you can see that the centerset faucet is a lavatory set that is 4" center to center from handle to handle.

1. Hot water inlet 2. Pop-up assembly 3. Cold water inlet

Washer less:

All faucets can be 'washer less' as they come in both the single- and two-handle type. In most washer less faucets, the control of the water flow is done by a cartridge or arrangement of seals that allow water to flow when the holes or ports are lined up. The design is such that the water flow is basically sheared off. Unlike 'washer' types, extra strength of pressure on the handle will not help stop the water flow. There are many different designs of washer less cartridges. Some foreign cartridges can be very expensive. Ceramic cartridges are becoming very popular. Ceramic cartridges have been around for over 20 years. Ceramics tend to last longer than other types of cartridges but can cost a lot more when replacing. Remember, all faucets will eventually leak. A good idea is to once or twice yearly, open and close all shut off valves under all faucets (if any). This will help keep them free of sediment and will allow them to be closed when needed. There tends to be less friction and wear and tear with a "washer less" faucet compared to the older washer-type faucet.

Alternate Mounting:

Wall mount faucets are designed to mount on the wall.	Backsplash faucets are designed for commercial/restaurant sinks that have a backsplash.
Close coupled wall mount faucets have a short inlet and are designed for non-freeze areas.	Slant back faucets are designed mainly for older sinks which have 45° angle faucet holes.
Deck mount faucets mount onto the top of the sink, with threaded shanks or bolts passing down through the mating holes.