As KrushBrother said. However, it looks like the person is going to use GameMaker regardless of what you say. If they care, it'd be worth mentioning the following about Construct Classic:
-Completely free and open source as well as a plugin SDK
-Some (basic) 3D support without any complex scripting
-Runs MUCH faster than any GameMaker game I've ever seen
-Supports pixel shader effects
-Some really nice plugins like R0j0hounds Texture Set plugin (allows a render-to-texture style effect)
-Games can be scripted with Python, but events alone can make a great game (GameMaker is pretty broken without resorting to GML programming)
-Game graphics can be more than just tile-based
The list is pretty endless, but for support and (definitely) stability GameMaker wins, simply because it has been going on for so long.
Edit: I disagree LavaWave, if you are making a full game you just need to know some limits, workarounds, and keep lots of backups. That's pretty much the same with any programming/game making tool. Construct Classic just needs a bit more time for refinement =]
Playing avi's I agree doesn't work as well as it could, but the 3D model object surpases the 3D Box Object. With R0j0hounds plugin you can even do animations