For pure 2D games (PC, Steam, Facebook) then Construct is perfect!
For iOS and android I believe it is good now (I have not tried the build in builder, just used C2 and it worked, but not perfect)
For 3D games it is big NO NO.
For console games also no no
Multiplayer games is possible. But I have still not seen any impressive multiplayer games made by construct, so maybe serious developers making those kind of games uses different engines.
To be honest construct is mostly for indie devs as I see it, but it sounds you are one so it will fit you perfectly.
Soon there will be a totally new runtime as well. If that will be an huge improvement with lots of new features and astonishing better performance, or just slightly better performance but lots of bugs we will see... Hopefully the first one!