Those of us who grew up with saccharin as our first "artificial" sweetener are sort of nostalgic for the taste. T@b changed its formula (slightly) in 1984 when it went from a pure saccharin formula to a saccharin/aspartame formula (still mostly saccharin, I think, based on taste tests). There was some outcry at the time about saccharin being carcinogenic in lab rats but I think that has since been disproven, but that was behind the drive to change the formula, and I think along with that, aspartame was seeking a market.
That said, see if you can get a hold of a can of T@b, then compare its flavor with that of Diet Coke. See which one you like better.
You’ve got me curious to try and find some T@b for a taste test. At the very least it would be a fun nostalgia trip.