I can to 1000% agree with what Arima has posted.
My Main Event Sheet that is used for every Combat Layout has 4500+ Events and well over 150 Objects. I stopped counting how often Construct crashed because of some "Argument".
Just like Arima said, the Memory keeps rising and this makes editing events on huge Layouts nearly impossible, seeing as it takes around 20 - 30 Seconds to actually edit / create a new Event!
The only way for me to get around this was to save every time after I made around 20 Actions in the Event Sheet Editor and then relboot construct, else it says Invalid Argument and Crashes.
Ofcourse this got severely on my nerves after a time and being able to make steady progress was impossible aswell, seeing as everything took so much time to edit because of much events and objects.
So now I always make a new Layout in a new .cap because creating events is super fast and Memory usage low. Then I need to copy the Layout to the Main Cap wich is a very annoying task, seeing as sometimes things get messed up. So I agree here with Arima aswell.
If those 2 things would be fixed, or even only the Memory Bug, then Construct would have absolutely no Problems creating a big Project in my Opinion. Those two things are the only things that bothers me, and I have been working for over 3/4 Year now. These were the only problems I had.
However though, in the end Construct is way more awesome than Game Maker or MMF.
Just thought I'd post this, may be of help or something.