sigh you see a lot of to-die-for renders at CGTalk. I use Vray, and while it does make your job easier, and it offers a lot more options, not even the best render engine can make an image look good without an awful lot of work on models, shaders, and lighting. If one hits Render without having spent a good amount of time on materials, expect to get a 'canned' look. Very few light sets will give any given image a good solution without a lot of tweaking and fussing.

The primary downfall of most less-than-good images, however, is a cohesive final image. Somewhere along the way, the artist loses the feel or point they set out to convey. Photo-real is great for arch-viz, not so much for a dreamy forest scene.

Bottom line, it doesn't matter if you're using MS Paint, or Maya, you need a clear vision of what you want, and you have to put in the time to achieve the look. And if that means learning how to properly compose an image, or years learning how to control lighting, or asking for help on how to build good shaders, that's what you have to do. This is one hobby (or career) that is definitely hard work.