Ultimately I'm a bit baffled cause I've tried using GM / GMS / GMS2 multiple times over the years and I think it's terrible.
I had a similar experience. I ended up choosing C2 because it was much easier to get started making games. Also, GM's Drag-n-Drop is more limited than Construct's event system and I wasn't in the mood to learn a new language, especially a proprietary language for a single app.
The new prices of GMS2? Forget about it. In order to do everything that C3 does, you would have to pay...
Desktop $99.99
GMS2 Mobile $399.99
GMS2 UWP $399.99
GMS2 Web $149.99
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Total = $1049.96 USD
That's 10 years of C3 subscriptions. I'm sure C4 will be out before then. ;)