I own Gamemaker Studio, Fusion 2.5 and Construct 2.
Construct is the cheapest and the best for my use. Comes with easy download and no fuss licensing etc.
Everytime I get to use the others I feel frustrated by something or the other, when I use Construct 2 I feel like a weight has been lifted. This goes from using the sites, tutorials upgrading licences etc.
Construct 2 makes game development fun.
There are issues or things I wish where different but with Ashley Tom and some members here doing amazing plugins etc, it's really non issues.
And this is where Scirra has a HUGE lead. The community and documentation as well as how professional things look (websites, forums, documentation, tutorials) esp in comparison with Clickteams stuff.
Funnily enough I really like the way Fusion 2.5 event system works...everything is exposed all the time. It's a great way too learn. I am in the minority but I can tell exactly whats what, however, because of the way it is it's also very limiting in some ways, although many, many good games have been made with it. FNAF 1-4 to name just one series.
I do feel competition will heat up with Fusion 3 and Construct 3.
Yves one of the Devs said that Fusion 3 will definitely release in 2016, so this year we get to see Fusion 3 and Construct 3 I bet.
My money is on Scirra though.
Gamemaker lost the plot somehow imho. it just got so fragmented in community and tool that unless you just code it gets frustrating fast. To me anyway. Not to mention both those two tools are very expensive.
Imho Construct 3 is where it's going to be at...although I really like Fusion for it's export options native...I understand what Scirra is trying to do, why, and the bet on HTML5.
I think it will pay off.
Ashley and team feels they know better than the community at what we need, rather than what we want. For the most part they might be right