Just like anything there are pluses and minuses to either approach. I have had success with using the event sheet but I always reach a point where, to me, it seems convoluted to try and accomplish some tasks.
The biggest pluses for me with using JS are that debugging the logic is much easier for me using the chrome debugger than using the construct debugger. However, the info it provides such as utilization and FPS are awesome. Also being able to utilize functionality that isn't available out of the box is a good use for JS, whether you game is just using a little bit of it or the whole application is in JS. In my game I am able to manage users and store there current state object utilizing the PlayFab service api.
The big downside to JS in construct is that there isn't a full blown development environment. It does provide excellent auto completion and syntax checking, but there aren't ways to search all files, refactor the name of a class and have it automatically rename all instances, find all references of a token, etc... So if you aren't careful with how you layout your code you can have a hard time finding things later on.
Overall I think it depends on what you are comfortable with, your experience with JS, and whether your game can benefit from a little JS or a lot of JS.
I have been programming in JS, C#, C++, and others for many years and find it easier for me.
If you have any additional question, just let me know.