I have PUR Simply Cake but haven't mixed with it yet. I should get on that!What about PUR simply cake and CAP. Cake batter?

CAP Cake Batter is excellent as is FW Cake Batter. CAP Cake Batter adds a nice light buttery note as well.
Used primarily as an additive at 0.5% - 0.75% CAP or FW will add moistness and mouthfeel to any mix. That's how I like to use it.