There's no evidence that either sucralose nor acesulfame potassium pose any threat to human health: www.cancer.gov/cancertopics/factsheet/Risk
You do want to limit your intake; the FDA has set a guideline to determine your acceptable daily intake for sweeteners like Sucralose. www.medicinenet.com/artificial_sweeteners/
"The FDA reviewed studies in human beings and animals and determined that sucralose did not pose carcinogenic, reproductive, or neurological risk to human beings. The acceptable daily intake (ADI) for sucralose was set at 5 mg/kg of body weight/day. To determine your ADI, divide your weight in pound by 2.2 and then multiply it by 50. For example, if you weigh 200 lbs., your weight in kg would be 91 (200 divided by 2.2) and your ADI for sucralose would be 455 mg (91 x 5)."
Enjoy your soda, but make sure you limit your intake and aim to get plenty of actual water. :)