Sucralose is currently one of six non-nutritive sweeteners and one of five artificial sweeteners approved by the FDA as well as the only one derived from sugar. Sucralose derives its name from sucrose, where it includes the chemical substitution of three chlorine atoms for three hydroxyl (hydrogen-oxygen) groups.  This chemical manipulation gives sucralose greater sweetness over sucrose without the calories, allowing it to be used as a non-nutritive sweetener. It is the fifth oldest sugar substitute – preceded by saccharin, cyclamate, aspartame, & acesulfame potassium – to gain FDA approval, dating back to its discovery in 1976 by researchers at Queen Elizabeth College – in London, UK – during a collaborative research program with UK sugar producer, Tate & Lyle, PLC. 
“Sucralose was approved for use in 15 food and beverage categories by the U.S. Food and Drug Administration (FDA) on April 3, 1998. The FDA expanded the uses for sucralose in 1999, approving it as a “general purpose” sweetener. Sucralose has also been approved for use in foods and beverages in over 80 countries including Canada, Australia, Japan, the European Union and Mexico.” [PDF] The Acceptable Daily Intake (ADI) for sucralose was set at 0-15 mg/kg body weight by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) in 1990 and by the Scientific Committee on Food (SCF) in 2000. [PDF2] To relate this to human consumption, “a standard 12-ounce can of diet soda would require only 70 milligrams (0.07g) of sucralose compared to a full-calorie version that would typically contain about 40g of sugar or high fructose corn syrup.”  For a 150 pound person, they would have to consume approximately 32 12-ounce cans of diet soda to hit the ADI.
Sucralose is listed as being 600 times sweeter than sugar, as well as tasting like sugar. “It has a clean, quickly perceptible, sweet taste that does not leave an unpleasant aftertaste.”  The chemical manipulation of sucrose leaves sucralose unrecognizable to the body as sugar, meaning almost all of it is excreted in the urine unchanged. However, there is varying degrees of sucralose that is metabolized by the body. [PDF3] For example, Dr. Mercola says to look at the research, where “15% of sucralose is absorbed into your digestive system and ultimately is stored in your body.”  It also does not break down when heated – like acesulfame potassium – meaning it can be used in cooking and baking. 
Coming from sugar, sucralose has gained a large amount of appeal for being an acceptable sugar alternative for people of all ages. “Sucralose has been extensively tested in more than 100 studies during a 20-year period and found to be a safe and remarkably inert ingredient. It can be used by all populations, including pregnant women, nursing mothers, and children of all ages. No population subgroup has been excluded from using sucralose. Sucralose is beneficial for individuals with diabetes because research demonstrates that sucralose has no effect on carbohydrate metabolism, short- or long-term blood glucose control, or insulin secretion.” [PDF4] To reiterate the message further, “sucralose is considered safe for all segments of the population, including people with chronic health problems such as diabetes. ” 
Some concerns have been raised over adding Chlorine molecules to sucrose, mostly due to general concern over synthetic food ingredients. A common response is that “many commonly consumed substances, including table salt (sodium chloride), contain chlorine; the presence of this element in a compound does not indicate that the compound is toxic. Sucralose is a safe, well-tested food additive. There are no unresolved scientific concerns about its use.” [PDF5] Further, “the chlorine in sucralose does not separate in the body, nor does sucralose accumulate in the body. In fact, it is the presence of these chlorine atoms that prevent sucralose from being broken down in the body for energy, thus, making sucralose non-caloric.” 
But going back to Dr. Mercola, what if that 15% we absorb is harmful to us? Some of us may absorb more than 15%, while others absorb less. Mercola summed it up well when he said, “we all have our own unique biochemical make-up.”  If you are feeling side affects while using sucralose, this may be why. If you don’t have any side effects, which can be proven by removing or adding sucralose and monitoring personal health, then it may not cause any harm. Betty Kovacs, MS, RD, has posted an article that includes the cons of sucralose, in her own words. She has stated the use of the book “Sweet Deception” as a reference, which is a book on artificial sweeteners by.
For general statements that sucralose can cause side effects such as headaches, allergies, & gastrointestinal issues, there doesn’t seem to be any real scientific evidence. “No toxic effects have been seen in test animals, even in amounts equivalent in sweetness to more than 40 pounds of sugar per day for life.”  A combination of sucralose with other foods may cause concern, yet the compound has been found to be “an inert, nonreactive ingredient that does not interact with other food ingredients or drugs.”  For talks on carcinogenicity, which all artificial sweeteners are subject to, “over 30 studies have been completed to provide better understanding regarding the possibility that sucralose could lead to cancer. These studies demonstrate that sucralose is safe and not related to cancer.” [PDF4]
The justifications may be accurate, especially with a relatively new substance such as sucralose, but that doesn’t mean they’ll be accurate in the future. The chemical modification and percentage metabolized by the body could have long term effects. Mercola says, “there have only been six human trials to date & the longest trial lasted three months.” Not nearly enough time to have a comprehensive assessment of long-term use. The best case study would be people who have used sucralose for years, but none seem to exist.
Today, sucralose can be found in items such as, “soft drinks, juices, sauces, syrups, candy, desserts, baked goods and canned fruits. It is used in medicines, nutritional supplements and vitamins. ”  Also, “many foods and beverages also display the “Sweetened with SPLENDA®brand” logo on their packaging.” [PDF] Finally, “sucralose is available in supermarkets as a tabletop sweetener under the brand name SPLENDA in two forms – granular and packets. The granular tabletop sweetener can be used as a spoon-for-spoon replacement for sugar. It pours, measures, and cooks and bakes like sugar.”  Further more, packets are now available with one gram of added fiber.
Although SPLENDA is made from sucralose, it may have nutritive (which have calories) sugars added to it – such as dextrose & maltodextrin – which may be personally undesirable even in small amounts. Some may even have a mixture with aspartame, which carries – another potential risk, – in the eyes of many. The best way to know for sure is to read the labels on these products to see if you’re getting true sucralose, or a combination.
Here is a SPLENDA product list, which exceeds 6,000 products.