I got a job for a few months ago where I had to fix and improve a G-Develop 5 game. The job was for a bit more than 3 weeks.
It was indeed a very frustrating experience, yes, I get used to Construct 2 (and 3), but many things are totally not user friendly at all.
For example, figure out how to create a function was difficult, lack of proper documentation and lack of community talking about a topic like that.
Many things makes no sense to me, like why there is no ELSE? I had to create a variable to handle all the ELSEs of the project, I could have done the same thing 10 time faster in Construct.
Array aren't supported unless you install a plugin, and if I recall well, they are only a 1-dimension array. I had to create manually lots of conditions to simulate an Array. Thing that in construct takes just a few seconds instead of hours.
On the other hand there where a few cases where I could do things that aren't directly doable on Construct, even if I haven't totally investigate through it, perhaps I could try with JS.
For example, I could play a file that was on a website instead inside the project. I was also able to use synthetic voice with JS (but this I am quite sure I can try to do it with Construct as well).
As 
R0J0hound said, my opinion come after having used Construct for 8 years, so my skills aren't comparable to the ones on G-Develop5. However, if I think about my first attempt with Construct 8 years ago, and the recent ones with G-Develop5, Construct was much easier to pick up.
I want also to add that G-Develop5 is somehow similar to Construct, so coming from Construct has helped me a lot compared to when I moved to Construct with my Basic/Pascal/Cobol/Clipper and a month of Game Maker Studio experience.
Also when I used G-Develop, I had 8 more years of programming experience on my shoulders, compared to when I started with Construct. So G-Develop had indeed a big advantage, but still failed the comparison from the point of view of difficulty in starting with the program, and if you consider how much is easy to get frustrated in the first week and give up game development, I would definitely consider Construct as your option.
My usual advice to avoid to "waste" money is to start with the free version of Construct 2, then when the limitations stops your experiments and progress, move to the free version of C3 (register to have more events) and finally once you are ready, especially if you want to make a living with that, start with the C3 subscription.