Speck, if you are interested in the risks to one's health, there are many.
Dr. Russell Blaylock has written a book called, "Excitotoxins: The Taste That Kills".
Here is an article he wrote:
http://www.dorway.com/blayart1.txt
and another:
http://landofpuregold.com/the-pdfs/Excitotoxins.pdf
Here is one of many studies, showing that the formaldehyde which is formed in the body from what aspartame is made of, collects, cumulatively, in the body:
http://www.ncbi.nlm.nih.gov/pubmed/9714421
PubMed is a good place to look for studies, if one can pick through the data, who funded them, how the results are interpreted, what the controls for the trials were, etc.
Here is a website with lots of info about aspartame. This page shows that aspartame is not allowed in the European Union.
http://www.aspartame.ca/page_a2a.html
Splenda is no better. Splenda, sucralose, is chlorinated sugar, a chlorocarbon. It is chemically in the same family as DDT and other insecticides. A little research about the effects of chlorine and chlorocarbons got me off it, too.
Sugar alcohols also have their problems.
If you are serious about wanting to know what these chemicals are, and what they turn into, in your body, and what the effects are, the information is available. One has to read carefully, and sift the chaff from the wheat.
When I was getting myself off of diet sodas, I drank a little frozen apple juice in sparkling water or seltzer water. It gave me the fizzy factor and was refreshing.
I wish you perfect success in leaving them behind you.
We, human beings, are so attracted to the taste of sweet, and it can cause us many problems.
You can make lemonade out of water, fresh lemon juice, and a "tea" made from stevia leaves. You can grow stevia year-round quite easily in Livermore.
Sending you all best wishes.