I'll support GameStudio. In my books, it's the best engine that works with good quality works-out-of-the-box-and-ready-to-go templates that just work, even if it's something being recycled.

Other engines are confusing/need intense code learning/buggy or just not worth the money. I know GameStudio is a bit of a whammy with the cost ($800 I think for one of the versions) but hey, at least it's better than a version that lacks the basic key features.

Torque 3D may have beaten GameStudio to the mark, but it depends on the money you're willing to pay.