Updated: Jul 29, 2020
They are both insert materials so they do not impact the taste of coffee on their own.
However, the base they are kept on, makes all the difference - heated bases tend to spoil the taste of drip coffee after a while. Coffee tastes best if it is not subject to continuous heating after it has been brewed.
If the stainless steel carafe is a double walled one such as in some Breville models - to keep coffee hot for a longer time on a non heated base then it is a better option than a glass carafe. They are also not as fragile as glass carafes.
Image: The Breville Precision Brewer with a SS thermal carafe
Glass carafes on the other hand tend to retain heat better than simple stainless carafes in general and provide the added convenience of visual confirmation of coffee quantity.