Interesting.
With a long background in animation and UX design, I'm very sensitive to frames-per-second, responsiveness and overall feel and speed of an application. That's why I chose Construct in the first place, it achieved a higher frame rate and just felt smoother than any other game builder I had tried at the time.
That being said, I did notice a huge difference in the snappiness of the javascript code as opposed to events. It felt like a completely different engine and I had never felt that kind of responsiveness from this engine before.
It made me want to program a game entirely out of Javascript to achieve that kind of responsiveness.
It's interesting that you got something to perform 10x better using Javascript code rather than events alone...
I also program iOS apps using XCode and Swift and even then, I always find myself wishing the responsiveness was better on the touch screen. It's not quite instant. (I've seen it measured as high as 300ms in the worst cases.) It slightly slower on android. I just like really snappy responsive design. :) Javascript seems to achieve that with this engine. :)