Crispety-I have also tried the sugar free vanilla instant pudding and it tasted great. The only difference is that the sugar free instant pudding ingredients contained Splenda which actually tastes like sugar.
You can also bake an instant pudding cake. What you do is bake the cake like you normally do and then in the middle you place a layer of chilled instant pudding on top of the lower layer.
This way when the cake is ready you will taste the instant pudding filling. You also coat the rest of the cake like you would the way you add frosting. It will have a light airy taste like a Boston crème pie.