No need for things to get heated. I don't think anyone's trying to be antagonistic here.
As for the performance, construct games can run well but it requires making sure you optimize carefully, avoiding things like overdraw, doing collisions on unnecessary objects, etc. I have an action RPG prototype that runs at a smooth 60 frames per second on an iPhone 4S and iPad 3. It can be done, but it does take some learning of how to optimize for it.